stihl ms 192 t - ramcottage.co.uk

STIH)

STIHL MS 192 T

2005-02

Contents

1. 2.

Introduction Safety Precautions

3

3.

Specifications

5

3.1 3.2 3.3 3.4 3.5

Engine Fuel System Ignition System Chain Lubrication Tightening Torques

5 5 5 5 6

4.

Troubleshooting

8

4.1 4.2

Clutch Chain Drive, Chain Brake, Chain Tensioner Chain Lubrication Rewind Starter Ignition System Carburetor Engine

8

4.3 4.4 4.5 4.6 4.7 5.

Chain/ Spiked Bumper

Engine

8.1 8.2 8.2.1 8.2.2 8.2.3 8.3 8.4 8.4.1 8.4.2 8.5 8.5.1 8.5.2 8.5.3 8.6 8.6.1 8.6.2 8.7

Muffler / Spark Arresting Screen Leakage test Preparations Vacuum test Pressure test Oil Seals Engine Removal Installation Crankshaft Removal Installation Crankshaft / Bearing Piston Removal Installation Piston rings

27 27 28 28 29 30 31 31 32 34 34 35 37 39 39 39 41

11.1 11.2 11.3

9.

Ignition System

9.1 9.1.1

Ignition Module Removing and installing Ignition Timing Testing the Ignition Module Ignition Lead / Spark Plug Boot Flywheel Short Circuit Wire Testing Removing and installing Troubleshooting, Ignition System

4

9 10 11 12 13 15

9.2 9.3 16 9.4

5.1 5.2 5.3 5.4 5.5

Chain and Chain Guide Tensioning the Chain Chain Catcher Bumper Spike Bumper Strips

16 17 17 17 18

9.5 9.6 9.6.1 9.6.2 9.7

6.

Clutch

18

6.1

Sprocket / Clutch Drum

20

7. 7.1 7.2 7.3

Checking Operation of Chain Brake

21

Removing and Installing Chain Tensioner Bar Mounting Stud

21 25 26

27

11.

8.

11.4 11.5

62 62 63

12.

Actuating Levers

63

12.1 12.2 12.3 12.4

Throttle Trigger / Interlock Lever / Throttle Rod Double Lever Switch Shaft Handle Housing

63 64 65 66

42

13.

Chain Lubrication

68

42

13.1 13.2 13.3 13.4 13.5

Pick-up Body Oil Suction Hose Oil Pump Valve Oil Tank Filler Cap

68 68 69 70 71

42 44

45 46 47 47 48 50 53

10.1 10.2

General Removing and Installing Pawls Rope Rotor Starter Rope / Grip Tensioning the Rewind Spring Replacing the Rewind Spring Starter Rope Guide Bushing

53

10.8

60 61

44

Rewind starter

10.7

60

Annular Buffer Front Handle / Spring AV Spring between Handle Housing / Engine Housing Clamp Loop

10.

10.3 10.4 10.5 10.6

Repairing the AV System

53 54 54 55 57 58 59

q © ANDREAS STIHL AG & Co. KG, 2005

MS 192 T

1

Contents

14.

Fuel System

72

14.1 Air Filter 14.1.1 Air Filter Base 14.2 Carburetor, Removing and Installing 14.2.1 Leakage Test 14.3 Carburetor Repair 14.3.1 Metering Diaphragm 14.3.2 Inlet Needle 14.3.3 Fixed Jet 14.3.4 Pump Diaphragm 14.3.5 Choke Shaft / Choke Shutter 14.3.6 Throttle Shaft / Throttle Shutter 14.3.7 Accelerator Pump 14.3.8 Adjusting screws 14.4 Carburetor Adjustment 14.4.1 Basic Setting 14.4.2 User Setting 14.5 Intake Elbow, Removing and Installing 14.5.1 Impulse Hose 14.6 Tank Vent 14.6.1 Testing 14.6.2 Removing and Installing 14.7 Fuel Intake 14.7.1 Pick-up Body 14.8 Fuel Hoses 14.8.1 Fuel Pump 14.8.2 Fuel Tank Filler Cap 14.8.3 Tank Housing, Removing and Installing

72 73

15.

16.

2

73 74 75 75 76 77 77 78 80 81 82 83 83 84 85 87 88 88 89 89 89 90 92 93 93

Special Servicing Tools

94

Servicing Aids

96

MS 192 T

Introduction

This service manual contains detailed descriptions of all the typical repair and servicing procedures for this power tool. Refer to the illustrated spare parts lists during all repair work. These lists show the installation position and order in which the individual parts and modules should be assembled. Refer to the latest edition of the relevant parts list to check the part numbers of any replacement parts required. A fault on the machine may be due to several causes. To help locate the fault, consult the chapter on "Troubleshooting" and the "STIHL Service Training System" for all function groups.

The special tools mentioned in the descriptions are listed in the chapter "Special Servicing Tools" of this manual. Use the part numbers to identify the tools in the STIHL Special Tools manual. It lists all the special servicing tools currently available from STIHL. Symbols are included in the text and pictures for greater clarity. The meanings are as follows: In the text: : = Action to be taken as shown in the illustration above the text – = Action to be taken but not shown in the illustration above the text In the illustrations:

Refer to the "Technical Information" bulletins for engineering changes which have been introduced since publication of this service manual. Technical information bulletins also supplement the parts list and service manual until an updated edition is issued.

A Item pointer (short) a Direction of movement (long arrow) b 4.2 = Reference to another chapter, i.e. to chapter 4.2 in this case. Service manuals and technical information bulletins are intended exclusively for the use of properly equipped repair shops. They must not be passed on to third parties.

MS 192 T

2 1 1

3

217RA000 TG

1.

Servicing and repairs are made considerably easier if the machine is mounted on assembly stand (3) 5910 890 3100. For this purpose, secure the clamp (2) 5910 890 2000 to the assembly stand with two screws (1). Engage the adjusting screw and stud in the outer holes of the clamp and secure the chainsaw with the nut (arrow). The sprocket cover and bar and chain must be removed first; pull the hand guard back against the front handle for this purpose. Always use original STIHL replacement parts. They can be identified by the STIHL part number STIH) logo and the STIHL parts symbol ( The symbol may appear alone on small parts.

3

2.

Safety Precautions

Specific national safety regulations and the safety instructions in the instruction manual must be observed if the machine has to be started up during maintenance or repair work. Petrol is highly inflammable and can also be explosive under certain conditions. Improper handling may result in burns and other serious injuries. Do not bring any fire, flame, spark or other source of heat near the fuel. All work with fuel must be performed outdoors only. Spilled fuel must be wiped away immediately.

4

MS 192 T

3.

3.1

Specifications

Engine MS 192 T

Displacement: Bore: Stroke: Engine power to ISO 7293 Max. permissible engine speed (with bar and chain): Idle speed: Clutch: Clutch engages at: Crankcase leakage test at gauge pressure: under vacuum

3.2

30.1 cm3 37 mm 28 mm 1.3 kW (1.8 HP) at 9500 rpm 13500 rpm 3000 rpm Centrifugal clutch without linings 4150 rpm 0.5 bar 0.5 bar

Fuel System Carburetor leakage test at gauge pressure: Operation of tank vent at gauge pressure: Fuel:

3.3

0.3 bar as specified in instruction manual

Ignition System Air gap between ignition module and fanwheel: Spark plug (suppressed): Electrode gap:

3.4

0.8 bar

0.15...0.35 mm NGK BPMR 7 A 0.5 mm

Chain Lubrication Fully automatic, speed-controlled oil pump with rotary piston Oil delivery rate:

MS 192 T

6.5 - 8.5 cm³ at 10,000 rpm

5

3.5

Tightening Torques

DG screws are used in polymer and light metal components. These screws form a permanent thread when they are installed for the first time. Screws can be removed and installed as often as necessary without impairing the strength of the screwed assembly, provided that the specified tightening torque is observed. For this reason, it is essential to use a torque wrench.

Fastener

Thread size

For component

Screw

DG 4x15

Screw Collar screw Screw Screw

D 6x13 DG 8x18 B 4.2x9.5 P 4x12

Nut

M5

Nut Nut

M5 M5

Nut Screw Screw Screw Screw Screw Screw

M5 P 6x19 P 4x12 P 6x19 DG 5x20 P 5x16 P 5x16

Screw Screw

P 5x16 P 5x16 M 8x1 L DG 5x20Z DG 4x20 P 4x12 P 5x29.6 DG 5x20 M 8X1 M 14x1.25 DG 4x20

Chain tensioner cover plate / engine housing Collar screw for guide bar, rear Collar screw for guide bar, front Cover plate/ screen/ muffler Cover/ sprocket cover/ engine housing tensioner Filter base/ handle housing, 1st stage aluminium Filter base/ handle housing, 1st stage Filter base/ handle housing, 2nd stage aluminium Filter base/ handle housing, 2nd stage Handle housing/ front handle Handle moulding/ handle housing Retaining plate/ loop/ engine housing Engine pan/ cylinder Bearing plug/ handle housing Bearing plug/ engine housing, sprocket side Bearing plug/ engine housing, fan side Fan housing/ engine housing Carrier Engine housing/ cylinder Oil pump/ engine pan Annular buffer, support/ engine housing Annular buffer/ handle housing Muffler / cylinder Flywheel/ crankshaft Spark plug Ignition module/ cylinder

Screw Screw Screw Screw Screw Nut Screw

6

Tightening torque Nm

Remarks

2,5 6,0 16,0 2,0 2,5 1,5 2,0 2,5 3,5 6,0 1,5 6,0 8,0 4,0 4,0 4,0 4,0 25,0 8,0 4,5 2,5 5,0 9,0 18,0 25,0 4,5

MS 192 T

Use the following procedure when refitting a DG screw in an existing thread: Place the screw in the hole and rotate it anticlockwise until it drops down slightly. Tighten the screw clockwise to the specified torque. This procedure ensures that the screw engages properly in the existing thread and does not form a new thread and weaken the assembly.

Screwdriver speed when used in plastic material: DG screws max. 500 rpm.

MS 192 T

7

4. 4.1

Troubleshooting Clutch

Problem

Cause

Remedy

Saw chain stops under load at full throttle

Clutch shoes badly worn

Install new clutch

Clutch drum badly worn

Install new clutch drum

Idle speed too high

Readjust with idle speed screw LA (anticlockwise)

Saw chain rotates at idle speed

Clutch springs stretched or fatigued Replace clutch springs or install new clutch Clutch spring hooks broken Loud noises

8

Replace clutch springs

Clutch springs stretched or fatigued Replace all clutch springs Needle cage damaged

Fit new needle cage

Clutch shoe retainer broken

Fit new retainer

Clutch shoes and carrier worn

Install new clutch

MS 192 T

4.2

Chain Drive, Chain Brake, Chain Tensioner

Problem

Cause

Remedy

Chain sprocket wears rapidly

Chain not properly tensioned

Tension chain as specified

Wrong chain pitch

Fit chain of correct pitch

Insufficient chain lubrication

Check chain lubrication

Chain sprocket worn

Fit new chain sprocket

Clutch shoes badly worn

Install new clutch

Clutch drum badly worn

Install new clutch drum

Brake band stuck

Check freedom of movement and function of brake band

Idle speed too high

Readjust with idle speed screw LA (anticlockwise)

Saw chain stops under load at full throttle

Saw chain rotates at idle speed

Clutch springs stretched or fatigued Replace clutch springs or install new clutch

Saw chain does not stop immediately when brake is activated

MS 192 T

Clutch spring hooks broken

Replace clutch springs

Brake spring stretched or broken

Fit new brake spring

Brake band stretched, worn or broken

Fit new brake band

Clutch drum worn

Install new clutch drum

9

4.3

Chain Lubrication

In the event of trouble with the chain lubrication system, check and rectify other sources of faults before disassembling the oil pump.

.

Problem

Cause

Remedy

Chain receives no oil

Oil tank empty

Fill up with oil

Oil inlet hole in guide bar is blocked Clean oil inlet hole

Machine losing chain oil

Oil pump delivers insufficient oil

10

Intake hose or pick-up body clogged or intake hose ruptured

Fit new intake hose and pick-up body

Valve in oil tank blocked

Clean or replace valve

Worm worn

Replace worm

Oil pump damaged or worn

Replace oil pump

Oil pump housing defective

Replace oil pump

Oil pump damaged or worn

Replace oil pump

Oil pump worn

Replace oil pump

MS 192 T

4.4

Rewind Starter

Problem

Cause

Remedy

Starter rope broken

Rope pulled out too vigorously as far as stop or over edge, i.e. not vertically

Fit new starter rope

Normal wear

Fit new starter rope

Rewind spring broken

Replacing the rewind spring

Spring insufficiently tensioned

Check rewind spring and increase tension

Very dirty or corroded

Clean or replace rewind spring

Starter rope cannot be pulled out far enough

Rewind spring overtensioned

Check rewind spring and reduce tension

Starter rope can be pulled out almost without resistance (crankshaft does not turn)

Guide peg on pawls or pawls themselves are worn

Fit new pawls

Spring clip fatigued

Fit new spring clip

Starter mechanism is very dirty

Thoroughly clean complete starter mechanism

Starter rope does not rewind

Starter rope is difficult to pull and rewinds very slowly

MS 192 T

11

4.5

Ignition System

Exercise extreme caution while carrying out maintenance and repair work on the ignition system. The high voltages which occur can cause serious or fatal accidents.

Problem

Cause

Remedy

Engine runs roughly, misfires, temporary loss of power

Spark plug boot is loose

Press boot firmly onto spark plug and fit new spring if necessary

Spark plug sooted, smeared with oil Clean the spark plug or replace if necessary

12

Incorrect air gap between ignition module and flywheel

Set air gap correctly

Flywheel cracked or has other damage or pole shoes have turned blue

Install new flywheel

Ignition timing wrong, flywheel out of adjustment, key in flywheel has sheared off

Install new flywheel

Weak magnetization in flywheel – pole shoes have turned blue

Install new flywheel

Irregular spark

Check operation of switch shaft and ignition module Faulty insulation on ignition lead or short circuit wire, check ignition lead / ignition module and replace if necessary. Check operation of spark plug Clean the spark plug or replace if necessary

Crankcase damaged (cracks)

Replace crankcase

MS 192 T

4.6

Carburetor

Problem

Cause

Remedy

Carburetor floods; engine stalls

Inlet needle not sealing. Foreign matter in valve seat or cone

Remove and clean inlet needle or clean carburetor

Inlet control lever sticking on spindle

Restore easy movement of inlet control lever

Helical spring not located on nipple of inlet control lever

Remove the inlet control lever and refit it correctly

Perforated disc on diaphragm is deformed and presses constantly against the inlet control lever

Fit a new metering diaphragm

Idle jet too lean

Turn low speed screw L anticlockwise (richer), until engine accelerates smoothly

Main jet too lean

Turn high speed screw H anticlockwise (richer), no further than stop

Inlet control lever too low (relative to correct installed position)

Set inlet control lever flush with top edge of housing

Inlet needle sticking to valve seat

Remove inlet needle, clean and refit

Diaphragm gasket leaking

Replace diaphragm gasket

Metering diaphragm damaged or shrunk

Fit new metering diaphragm

Impulse hose damaged or kinked

Fit new impulse hose

Poor acceleration

MS 192 T

13

Problem

Cause

Remedy

Engine will not idle, idle speed too high

Throttle shutter opened too wide by idle speed screw LA

Reset idle speed screw LA correctly

Oil seals / crankcase leaking

Seal or replace oil seals / crankcase

Idle jet bores or ports blocked

Clean the carburetor

Idle jet too rich or too lean

Set low speed screw L correctly

Setting of idle speed screw incorrect – throttle shutter completely closed

Reset idle speed screw LA correctly

Air filter dirty

Clean the air filter

Throttle shutter not opened fully

Check linkage

Tank vent faulty

Clean tank vent or replace if necessary

Fuel pick-up body dirty

Clean the pick-up body or replace if necessary

Fuel strainer dirty

Clean fuel strainer in carburetor or replace if necessary

Leak in fuel line between tank and fuel pump

Seal connections or install a new fuel line

Setting of high speed screw H too rich

Turn the high speed screw H clockwise (leaner) – max. up to the stop.

Main jet bores or ports blocked

Clean the carburetor

Pump diaphragm damaged or fatigued

Fit new pump diaphragm

Impulse hose damaged or kinked

Fit new impulse hose

Engine stops when idling

Engine speed drops quickly under load – low power

14

MS 192 T

4.7

Engine

Always check and, if necessary, repair the following parts before looking for faults on the engine: – – – –

Air filter Fuel system Carburetor Ignition System

Problem

Cause

Remedy

Engine does not start easily, stalls at idle speed but operates normally at full throttle

Oil seals in crankgear damaged

Replace the oil seals

Crankcase leaking or damaged (cracks)

Seal or replace the crankcase

Piston rings worn or broken

Replace piston rings

Muffler / spark arresting screen carbonized

Clean the muffler (inlet and exhaust), replace spark arresting screen, replace muffler if necessary

Air filter dirty

Replace air filter

Fuel / impulse hose severely kinked or damaged

Fit new hoses and route them without kinks

Insufficient cylinder cooling. Air inlets in fan housing blocked or cooling fins on cylinder very dirty

Thoroughly clean all cooling air openings and the cylinder fins

Engine does not deliver full power or runs erratically

Engine overheating

MS 192 T

15

5. 5.1

Chain/ Spiked Bumper Chain and Chain Guide

1

– Reassemble remaining parts in reverse order.

1

– Tension the chain, b 5.2

2

217RA002 TG

217RA003 TG

– Tightening torques, b 3.5

: Slide the guide bar (1) towards the clutch and remove the chain from the guide bar.

Wear protective gloves – risk of injury – : Disengage the chain brake by pulling the hand guard (1) towards the front handle until it engages.

– Remove the guide bar (1). – Remove the chain (2) via the sprocket.

217RA004 TG

– Reassemble parts in reverse order.

: Unscrew the hex nut (arrow).

: Unscrew the nut (arrow) and remove the sprocket cover (1).

16

217RA021 TG

1

217RA001 TG

: Turn the screw anticlockwise to relax the chain.

: Fit the sprocket cover, ensuring that the peg (arrow) engages in the hole.

MS 192 T

5.2

Tensioning the Chain

5.3

Chain Catcher

5.4

Bumper Spike

1

2

217RA006 TG

217RA350 TG

217RA076 TG

1

: Turn the screw clockwise to tension the chain.

Sprocket cover with integrally moulded chain catcher (1).

– Remove the sprocket cover and bar and chain, b 5.1

: Tighten the hex nut (arrow).

If the chain catcher has broken (2), file down the stub and replace with a replacement chain catcher (3).

– Remove the chain catcher, b 5.3 : Remove the screw (arrow). : Remove the spiked bumper (1).

3

217RA005 TG

1

217RA007 TG

– Reassemble parts in reverse order.

The chain (1) is correctly tensioned when it rests against the underside of the chain guide (arrow) and can be pulled over the guide bar by hand when the chain brake is released.

– Remove the sprocket cover and bar and chain, b 5.1

If the chain is tensioned excessively, this may result in damage to the chain, guide bar and sprocket, as well as its needle bearing.

– Reassemble parts in reverse order.

MS 192 T

: Remove the screw (arrow). : Remove the chain catcher (3).

17

Bumper Strips

6.

Clutch

– Troubleshooting, b 4.1

Bumper strips are fitted on the engine housing to guide the saw chain.

– Remove the sprocket cover and bar and chain, b 5.1

Worn bumper strips must be replaced, otherwise the engine housing may be damaged. Remove the sprocket cover and bar and chain, b 5.1

217RA010 TG

5.5

1 : Unscrew the spark plug (1).

1

: Prise off the bumper strips (1) with a suitable tool.

: Release the twist lock (arrow). : Remove carburetor box cover (1) to the rear.

217RA011 TG

217RA008 TG

1

217RA071 TG

1

1 : Push the locking strip (1) 0000 893 5903 into the spark plug hole so that "OBEN-TOP" faces down.

: Insert the bumper strips so that the peg is aligned in the recess (arrows).

: Apply a suitable tool to the tab (arrow) to prise the boot off the spark plug (1).

217RA012 TG

1

217RA009 TG

217RA083 TG

1

: Unscrew the clutch (1). The clutch has a left-hand thread.

– Reassemble remaining parts in reverse order.

18

MS 192 T

1

2

2

1

Disassembly : Use hook (2) 5910 890 2800 to remove the clutch springs (1).

: Slip the retainers (1) onto the clutch shoes.

217RA019 TG

217RA013 TG

217RA016 TG

1

: Attach one end of the clutch spring (1) to the clutch shoes. : Use the hook (2) 5910 890 2800 to attach the other end of the spring and press it firmly into the clutch shoe.

1

2

– Pull the clutch shoes off the carrier. : Pull the retainers (1) off the clutch shoes.

217RA017 TG

217RA014 TG

1

: Fit the clutch shoes over the arms (1) so that the series number (2) is on the same side as the raised hexagon (arrow).

– Clean all parts. – Replace any damaged parts.

MS 192 T

217RA020 TG

217RA018 TG

: Clamp the clutch in a vice (arrow).

11 37

217RA015 TG

1137

1137

The tips of the retainers (arrows) must match one another on the side with the raised hexagon and the series numbers must be visible on the clutch shoes.

19

6.1

Sprocket / Clutch Drum

1

: Fit the clutch on the crankshaft stub so that the raised hexagon (arrow) is visible.

– Remove the clutch, b 6

: Screw the clutch (1) with hexagon (arrow) onto the crankshaft stub and tighten it down. : Tightening torques, b 3.5 – Pull the locking strip out of the cylinder.

: Draw the sprocket (1) off the crankshaft stub.

If there are distinct signs of wear on the inside diameter of the sprocket (1), the remaining thickness must be measured. The sprocket must be replaced if less than 80% of the original thickness remain. – Reassemble parts in reverse order.

217RA024 TG

217RA022 TG

!

80%

– Examine the sprocket (1) for signs of wear.

1

1

100%

148RA101 VA

217RA023 TG

217RA084 TG

1

: Remove the needle cage (1) from the sprocket. – Clean the needle cage and crankshaft stub with standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons.

1

217RA058 TG

– Reassemble remaining parts in reverse order.

– Grease the needle cage and crankshaft stub, b 16 : Slip the needle cage (1) onto the crankshaft stub.

20

MS 192 T

217RA059 TG

1

: Slip sprocket (1) onto crankshaft stub.

Checking Operation of Chain Brake

The chain brake is one of the most important safety devices on the chainsaw. Its efficiency is measured in terms of the chain braking time, i.e. the time that elapses between activating the brake and the saw chain coming to a complete standstill. The shorter the braking time, the better the efficiency and protection offered against being injured by the rotating chain. The coefficient of friction is impaired by contamination (with chain oil, chips, fine particles of abrasion, etc.) and smoothing of the friction surfaces on the brake band and clutch drum. This in turn reduces the frictional forces and thus prolongs the braking time. A fatigued or stretched brake spring has the same negative effect.

217RA060 TG

– Start the engine.

The sprocket must engage the studs (arrow) of the wormwheel. – Reassemble remaining parts in reverse order.

7.1

Removing and Installing

1

217RA025 TG

7.

Removal – Troubleshooting, b 4.2 – Remove the sprocket cover and bar and chain, b 5.1 : Engage the chain brake by pushing the hand guard (1) downwards. The brake spring of the brake band is now relaxed.

– With the chain brake activated (locked), open the throttle wide for a brief period (max. 3 seconds) – the chain must not rotate. – With the chain brake released, open the throttle wide and activate the brake manually – the chain must come to an abrupt stop. The braking time is in order if deceleration of the saw chain is imperceptible to the eye.

217RA026 TG

If the chain brake does not operate properly, see troubleshooting chart, b 4.2.

: Take out the screws (arrows).

MS 192 T

21

– Draw the hand guard (1) out through the opening in the cover (arrow).

: Remove the cover (1).

Install a new brake band if there are noticeable signs of wear (large areas on inside diameter and/or parts of outside diameter) and its remaining thickness is less than 0.6 mm.

1

217RA028 TG

: Carefully ease the brake spring (1) off the anchor pin (arrow).

2

217RA030 TG

1

217RA032 TG

2

217RA321 TG

217RA027 TG

1

: Remove the inlay (1) and leaf spring (2).

: Remove the E-clip (arrow).

: Unhook the brake spring (1) from the brake lever (2).

Clean all disassembled parts with a little standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons.

1

– Examine the inlay and leaf spring and replace if necessary.

: Disconnect the brake band (1) from the lever (arrow) and remove it.

2

217RA031 TG

217RA029 TG

1

: Remove the hand guard (2) with lever (1) from the pivot pins. – Pull the lever out of the hand guard.

22

MS 192 T

1

1

1

217RA324 TG

217RA322 TG

217RA033 TG

Wet the inlay (1) with Loctite before fitting it, b 16

a

: Pull the pin (1) out of the cover with a suitable tool.

: Carefully drive the pin (1) home, tapping lightly, until value "a" approx. 4.3...4.7 mm is reached.

: Press the inlay (1) as far as possible into the opening in the cover.

The pin must be driven in squarely.

1

1

: Place the leaf spring (1) in the opening (arrow). – Lightly grease both the leaf spring and the pin of the inlay.

– Wet the knurled area of the new pin (1) with Loctite before fitting it, b 16 : Position the new pin (1) in the bore so that the knurling on the pin meshes with the existing knurling in the bore. Turn the pin back and forth as necessary.

217RA065 TG

: Prise off the bumper strip (1) with a suitable tool. – Check the bumper strip and replace it if necessary. – Reassemble parts in reverse order.

1

217RA035 TG

The anchor pin must be replaced if the groove in the brake spring anchor pin is worn. Proceed as follows:

217RA323 TG

217RA034 TG

1

: Slide the lever (1) through the opening in the cover.

MS 192 T

23

Coat all sliding and bearing points with STIHL multi-purpose grease, b 16

1

217RA036 TG

217RA041 TG

Do not grease the brake band.

2

: The turns of the brake spring must lie tightly against one another when relaxed. If this is not the case, replace the brake spring.

The forked opening (2) must face towards the brake band. : Insert the lever (1) in the side of the bearing boss (arrow).

Check correct position of the protective tube.

1

1

a = 31 mm b = 44 mm

Ensure that the holes in the lever inside the hand guard are lined up.

217RA039 TG

217RA037 TG

2

: Attach the brake band (1) to the brake lever (arrow).

: Slip the bearing boss of the hand guard (1) and lever (2) onto the pivot pins.

1

When fitting the parts, ensure that the cam (arrow) on the hand guard is guided past the leaf spring.

24

: Insert the brake band (1) in the opening (arrow).

217RA042 TG

217RA040 TG

1

217RA038 TG

1

: Attach the brake spring (1) to the brake lever (arrow).

MS 192 T

7.2

Chain Tensioner

– Remove the sprocket cover and bar and chain, b 5.1

1

– Troubleshooting, b 4.2

217RA045 TG

217RA043 TG

2

1

: Use the assembly tool (2) 1117 890 0900 to attach the brake spring (1) to the anchor pin (arrow).

: Pull the complete chain tensioner (1) out with a suitable tool.

– Reassemble remaining parts in reverse order.

1 4 3

2

2

1 217RA044 TG

– Check operation of the chain brake, b 7

217RA047 TG

Before fitting the sprocket cover, pull the hand guard up until it engages. The chain brake is now open and can be slipped over the sprocket.

: Turn the spur gear (2) clockwise until the tensioner slide (1) makes contact on the right and the screw (arrow) is revealed.

: Examine the thrust pad (1), spur gear (2), adjusting screw (3) and tensioner slide (4) and replace if necessary.

217RA046 TG

217RA048 TG

1

: Remove the screw (arrow).

MS 192 T

: Pull the thrust pad (1) off the adjusting screw.

25

7.3

: Pull the spur gear (1) out of the hole in the cover (2).

– Clean all disassembled parts with a little standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons. Replace any damaged or worn parts.

217RA053 TG

217RA052 TG

1

217RA049 TG

2

Bar Mounting Stud

1

– Remove the sprocket cover and bar and chain, b 5.1 – Fit the stud puller on the collar stud (1).

Always replace the adjusting screw and spur gear together. – Ensure that the parts are installed in the correct order.

1

: Turn the adjusting screw (arrow) until the tensioner slide has been unwound completely.

– Coat the threads and gear wheels with STIHL multi-purpose grease, b 16 – Reassemble remaining parts in reverse order. – Check correct functioning again.

217RA054 TG

217RA050 TG

– Check correct functioning.

: Push the stud puller (1) 5910 893 0501 over the collar stud as far as possible and unscrew the collar stud anticlockwise. – Reassemble parts in reverse order.

2

1

– Fit the collar stud and tighten it down firmly.

217RA051 TG

– Tightening torques, b 3.5 – Reassemble remaining parts in reverse order.

: Remove the adjusting screw (1) from the cover (2).

26

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8.2

8. 8.1

Engine Muffler / Spark Arresting Screen Check and if necessary repair the fuel supply, carburetor, air filter and ignition system before looking for faults on the engine.

Leakage test

Defective oil seals and gaskets or cracks in housing are the usual causes of leaks. Such faults allow supplementary air to enter the engine and upset the fuel-air mixture.

– Troubleshooting, b 8.1 217RA057 TG

– Remove the sprocket cover and bar and chain, b 5.1

This makes adjustment of the prescribed idle speed difficult, if not impossible. Moreover, the transition from idle speed to part or full throttle is not smooth.

: Take out the screws (arrows).

Always start with the vacuum test and then continue with the pressure test.

: Remove the screw (arrow).

217RA061 TG

217RA055 TG

The crankcase can be thoroughly checked for leaks with the carburetor and crankcase tester and the vacuum pump.

– Remove and examine the muffler, replace if necessary. – Clean the sealing faces. A gasket is not fitted between muffler and cylinder.

1 2

217RA056 TG

– Reassemble parts in reverse order.

: Remove the cover plate (2) and spark arresting screen (1) if fitted. – Clean the spark arresting screen (1) or replace if necessary.

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27

8.2.1

Preparations

8.2.2

– Remove the sprocket cover and bar and chain, b 5.1

2

– Set the piston to the top dead centre. This can be checked through the inlet port.

1 217RA063 TG

– Fit the spark plug and tighten it down firmly.

Vacuum test

Oil seals tend to fail when subjected to a vacuum. In other words, the sealing lip lifts away from the crankshaft during the piston's induction stroke because there is no internal counterpressure. An additional test can be carried out with the vacuum pump to detect this kind of fault.

: Ensure that the sleeve (1) and washer (2) are in place.

1

1

: Undo the screws (arrows). : Fit the sealing plate (1) 0000 855 8106 between the muffler and cylinder exhaust port and tighten down the screws moderately. The sealing plate must fill the full width between the screws.

: Remove the socket head screw (1) from the test flange 1128 850 4200.

217RA067 TG

217RA062 TG

217RA064 TG

1

: Connect the suction hose (1) of the vacuum pump 0000 850 3501 to the nipple (arrow).

1

– Remove the carburetor, b 14.2 0,4 0,6 400 500

0,8

600

300

0,2

200 100

700

0

– Fit the test flange 1128 850 4200 (1). : Screw on the nuts (arrows) and tighten them down firmly.

28

217RA069 TG

217RA066 TG

1,0

1 2 : Close the vent screw (1).

: Operate lever (2) until the pressure gauge (arrow) indicates a vacuum of 0.5 bar.

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8.2.3

Carry out the same preparations as for the vacuum test, b 8.2.2

0,4 0,2 0

– After finishing the test, open the vent screw and disconnect the hose.

0,8 1,0

: Pump air into the crankcase with the rubber bulb until the gauge (arrow) indicates a pressure of 0.5 bar. If this pressure remains constant for at least 20 seconds, the crankcase is airtight.

– Remove the test flange. – Install the carburetor, b 14.2 – Release the muffler and pull out the sealing plate. – Tighten down the muffler.

0,6

217RA068 TG

If the vacuum reading remains constant, or does not decrease by more than 0.3 bar within 20 seconds, it may be assumed that the oil seals are in good condition. If the vacuum in the crankcase is reduced further, the oil seals must be replaced.

Pressure test

– If the pressure drops, the leak must be located and the faulty part replaced.

1

– Reassemble remaining parts in reverse order.

217RA067 TG

– Tightening torques, b 3.5 – Continue with pressure test b 8.2.3 : Connect pressure hose (1) of tester 1106 850 2905 to nipple (arrow).

To find the leak, coat the suspect area with oil and pressurize the crankcase. Bubbles will appear if a leak exists. – After finishing the test, open the vent screw and disconnect the hose of tester 1106 850 2905. – Continue with vacuum test b 8.2.2

146RA063 VA

1

: Close vent screw (1) on the rubber bulb.

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29

8.3

Oil Seals

Clutch side – Clamp the puller arms. – Remove the sprocket cover and bar and chain, b 5.1

– Pull out the oil seal.

2

217RA085 TG

1

– Remove the clutch, b 6

Avoid damage to the crankshaft stub.

Use oil seal (1) 9639 003 1206 for installation on the closed crankcase. Use oil seal (2) 9639 003 1205 for installation on the open crankcase.

– Clean the sealing face with a little standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons.

– Remove the oil pump, b 13.3

– Grease the sealing lips of the oil seal, b 16

It is not necessary to disassemble the complete engine in order to replace the oil seals.

1

Ignition side – Remove fan housing, b 10.2

217RA294 TG

– Remove the flywheel, b 9.5

217RA070 TG

2

– Apply sealing compound to the outside diameter of the oil seals, b 16 : Use the press sleeve (2) 4112 893 2401 to install the oil sleeve (1). The seating face must be flat and free from burrs.

– Free off the oil seal in its seat by tapping it with a suitable tube or a punch. : Apply puller 5910 890 4400 with No. 3.1 jaws 0000 893 3706. – Clamp the puller arms. – Pull out the oil seal. Avoid damage to the crankshaft stub.

217RA274 TG

– Turn the crankshaft through several times after approx. 1 minute.

– Free off the oil seal in its seat by tapping it with a suitable tube or a punch.

– The crankshaft taper must be free from grease, therefore clean it with a little standard solventbased degreasant not containing any chlorinated or halogenated hydrocarbons.

– Clean the sealing face with a little standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons. – Grease the sealing lips of the oil seal, b 16

– Reassemble remaining parts in reverse order. : Apply puller 5910 890 4400 with No. 3.1 jaws 0000 893 3706. 30

MS 192 T

8.4 8.4.1

Engine Removal

1

217RA088 TG

– Apply sealing compound to the outside diameter of the oil seals, b 16

The complete engine must be removed before disassembling the piston or cylinder.

So that the oil seal can be pressed in as far as possible, the flat side of the press sleeve (arrow) must be aligned with the shoulder on the crankcase.

– Remove the sprocket cover and bar and chain, b 5.1

– Reassemble remaining parts in reverse order.

– Remove the muffler, b 8.1 – Remove the clutch, b 6 – Remove the oil pump, b 13.3 – Remove fan housing, b 10.2

1 217RA107 TG

– Turn the crankshaft through several times after approx. 1 minute.

– Remove the ignition module, b 9.1 – Remove the flywheel, b 9.5

: Prise off the supporting plate (1) with a suitable tool.

1

217RA103 TG

1

: Remove the cover (1).

MS 192 T

: Remove the screw (arrow).

217RA109 TG

: Press in the oil seal (2) with press sleeve (1) 4112 893 2401.

217RA108 TG

217RA086 TG

2

: Lift the handle housing (1) slightly and pull the manifold off the intake stub (arrow).

31

8.4.2

Installation

: Pull out the insulating plate (1), pressing the locking lug together at the bottom guide (arrow).

: Remove the screws (arrows) from underneath the engine housing.

217RA152 TG

217RA106 TG

217RA072 TG

1

: Push engine into engine housing.

: Remove the screws (arrows) on the carburetor side.

: Pull the engine out of the engine housing.

32

217RA153 TG 217RA105 TG

: Lift the handle housing slightly so that the intake stub can be positioned in relation to the manifold when fitting the engine.

217RA110 TG

: Lift the handle housing slightly until the manifold flange lifts off the intake stub.

217RA105 TG

: Disconnect the impulse hose (1) from the stub (arrow).

217RA153 TG

217RA104 TG

1

: Fit the screws (arrows) and tighten them down only moderately.

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– Tightening torques, b 3.5

: Fit the screws (arrows) and tighten them down only moderately.

217RA021 TG

217RA106 TG

– Remove the sprocket cover again. – Mount the machine on the assembly stand again and continue with the installation procedure.

: Guide the peg (arrow) into the hole and fit the sprocket cover.

Before tightening the screws down firmly, the engine must be centred in relation to the sprocket cover and guide bar.

217RA352 TG

1

217RA271 TG

1

: The pin (1) must be lined up with the hole (arrow) when fitting the sprocket cover.

: Push the manifold (1) onto the intake stub. – Coat the manifold with STIHL Press Fluid, b 16

– Fit the guide bar.

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217RA272 TG

: Unscrew the nut (arrow) and remove the machine from the assembly stand.

217RA351 TG

217RA357 TG

1

: Tighten down the nut (arrow) and secure the sprocket cover (1).

The tab (arrow) must point towards the saw chain.

– Now tighten down the screws securing the engine.

: Press in the supporting plate (1).

1

33

8.5 8.5.1

Crankshaft Removal

: Push the insulating plate (1) into the guides (arrows) until it engages at the bottom.

Ensure that the supporting plate rests securely on the engine housing at all points (arrows).

217RA111 TG

217RA273 TG

217RA158 TG

1

: Take out the screws (arrows).

: Insert and tighten down the screw (1).

217RA112 TG

1

217RA156 TG

– Reassemble remaining parts in reverse order.

: Apply a suitable tool at the projections (arrows) of the engine pan, then tap lightly to release and lift off the engine pan.

– Tightening torques, b 3.5

217RA157 TG

217RA113 TG

1

: Connect the impulse hose (1) to the stub (arrow).

: Remove the crankshaft from the bearing seats (arrows).

34

MS 192 T

8.5.2

Installation

1 1

217RA142 TG

: Pull the oil seals (arrows) off the crankshaft stubs.

– Coat the piston, piston rings and inside of cylinder with oil. : Use the clamping strap (1) 1137 893 2600 to compress the rings around the piston. The clamping strap (1) must be fitted so that the arrow (2) points towards the cylinder exhaust port and is lined up with the arrow (arrow) at the bottom of the piston.

217RA115 TG

– Check that the piston rings have been installed correctly.

217RA144 TG

217RA114 TG

2

For clarity, the piston is not shown in this illustration of the clamping strap fitted in the cylinder. : Insert the clamping strap with piston in the cylinder so that the tab (1) on the clamping strap engages the correspondingly shaped recess (arrow). When sliding the piston into the cylinder, ensure that the clamping strap firmly encloses the piston and that none of the piston rings protrudes. – risk of breakage –

MS 192 T

217RA145 TG

217RA143 TG

: Carefully pull the crankshaft and piston out of the cylinder.

: Align the piston and crankshaft before inserting them in the cylinder.

– Slide the piston into the cylinder, the clamping strap moves backwards at the same time.

The cylindrical crankshaft stub (arrow) must point towards the cylinder exhaust port.

: Remove the clamping strap.

35

: Check and clean the mating faces (arrows) on the cylinder.

Use oil seal (1) 9639 003 1206 for installation on the closed crankcase. Use oil seal (2) 9639 003 1205 for installation on the open crankcase.

Mating faces must be absolutely clean and undamaged. Parts with damaged mating faces must be replaced.

217RA151 TG

1

217RA085 TG

217RA146 TG

2

: Fit the crankshaft with bearings and oil seals in the bearing guides on the cylinder, taking care to ensure that the oil seals are flush (arrow).

217RA149 TG

217RA147 TG

Whenever the engine pan has been disassembled, the mating faces must be cleaned and fresh sealing compound applied, b 16

: Slip new oil seals onto the crankshaft stub with the open side facing the crankshaft.

– Check and clean the mating faces on the engine pan. Mating faces must be absolutely clean and undamaged. Parts with damaged mating faces must be replaced. : Apply sealing compound to the groove on the circumference (arrows) b 16

217RA116 TG

217RA150 TG

1

Before closing the crankcase, ensure that the cylindrical crankshaft stub (1) is on the side of the cylinder exhaust port (arrow).

: Apply sealing compound to the outside diameter (arrows) of the oil seals, b 16

36

MS 192 T

8.5.3

Crankshaft / Bearing

– Remove the engine, b 8.4.1

3

: Place the engine pan on the sealing surface of the cylinder, ensuring that the lug (arrow) faces the cylindrical crankshaft stub (1).

2

1

376RA128 TG

1

217RA148 TG

– Remove the crankshaft, b 8.5.1

: The crankshaft (1), connecting rod (2), the needle bearing between them and the needle bearing (3) form an inseparable unit. They must always be replaced as a complete unit. The deep groove ball bearings and oil seals must always be replaced when installing a new crankshaft.

217RA111 TG

217RA118 TG

1

So that the sealing compound is distributed uniformly, fit the screws and gently press the engine pan down.

: Remove the ball bearing (1) and washer.

– Before installing the crankshaft, clean it with standard solventbased degreasant not containing any chlorinated or halogenated hydrocarbons.

: Tighten the screws (arrows) down crosswise. – Tightening torques, b 3.5 Avoid damage to the crankshaft stub.

– Install the engine, b 8.4.2 – Reassemble remaining parts in reverse order.

MS 192 T

1 376RA133 TG

1 376RA121 TG

– Clean the crankshaft stub with standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons.

: Remove the ball bearing (1) and washer.

: Fit the washer (1).

37

1

: Fit the ball bearing with the closed side (arrow) facing outwards.

: Fit the washer (1).

217RA119 TG

376RA122 TG

376RA132 TG

1

: If the ball bearing cannot be heated, it must be pressed in with a suitable sleeve (1) until the ball bearing rests against the washer.

– Heat the inner race of the deep groove ball bearing to approx. 150 °C (300 °F).

– Coat the needle bearing with oil. – Install the piston, b 8.6.2

– Slip the deep groove ball bearing onto the crankshaft stub as far as the washer.

– Install the crankshaft and oil seals, b 8.5.2

The ball bearing must be fitted rapidly as the heat is transmitted to the crankshaft stub and the inner raceway contracts again.

376RA120 TG

– Install the engine, b 8.4.2

: Fit the ball bearing with the closed side (arrow) facing outwards. – Heat the inner race of the deep groove ball bearing to approx. 150 °C (300 °F). – Slip the deep groove ball bearing onto the crankshaft stub as far as the washer.

376RA123 TG

1

The ball bearing must be fitted rapidly as the heat is transmitted to the crankshaft stub and the inner raceway contracts again.

: If the ball bearing cannot be heated, it must be pressed in with a suitable sleeve (1) until the ball bearing rests against the washer.

38

MS 192 T

8.6 8.6.1

Piston Removal

8.6.2

Remove the engine, b 8.4.1

2

Installation

1

Remove the crankshaft, b 8.5.1

: Push the piston pin (1) out of the piston with the assembly drift (2) 1114 893 4700.

– Coat the needle cage with oil. : Align the piston so that the side with the bulge for the snap ring (arrow) is on the same side as the tapered crankshaft stub (1). – Position the piston on the small end.

217RA124 TG

If the piston pin is stuck, lightly tap the end of the assembly drift with a hammer to loosen it. The piston must be held steady during this process to ensure that jolts are not transmitted to the connecting rod.

217RA134 TG

217RA126 TG

1

: Use a suitable tool to prise the hookless snap ring out at the recess (arrow).

: Apply the assembly drift (1) 1114 893 4700 to the opposite side of the snap ring.

: Remove the piston (1) from the connecting rod. – Inspect the piston rings and replace if necessary, b 8.7

MS 192 T

1

217RA127 TG

217RA125 TG

1

217RA135 TG

1

: Fit the assembly drift (1) 1114 893 4700, small diameter first, through the piston hole and small end (needle cage) and line up the piston.

39

1

: Fit the piston pin (2) on the small diameter of the assembly drift (1) and slide it into the piston.

217RA138 TG

2

: Push the slotted diameter of the sleeve over the magnet and snap ring. The inner pin (1) must point towards the flat face (2) of the tool's shank.

217RA140 TG

1

217RA136 TG

2

: Apply assembly tool 5910 890 2210 to the piston boss with the taper sleeve, hold the piston steady and press the tool shank home until the snap ring slips into the groove.

: Remove the sleeve (1) from assembly tool 5910 890 2210.

217RA139 TG

1

217RA137 TG

The tool must be precisely aligned in axial direction of the piston pin.

: Press the assembly tool down in the sleeve until the magnet is at the end of the guide slits. Stand the tool on a suitable surface (wooden board).

: Attach the snap ring (1) to the magnet (2) and align it so that the snap ring gap is on the flat side (arrow).

: Remove the sleeve and push it as far as possible over the opposite end of the assembly tool's shank.

2

217RA141 TG

1

376RA111 TG

2

376RA327 TG

1

The snap ring (1) must be fitted in such a way that the snap ring gap (arrow) does not coincide with the recess (2).

The inner pin must point towards the flat face. 40

MS 192 T

8.7

Piston rings

– Remove piston, b 8.4.1

217RA117 TG

217RA131 TG

– Remove piston rings from piston.

: Position the piston rings so that the radii at the ring gaps meet at the fixing pins (arrows) in the piston groove.

– Inspect the piston rings and replace if necessary, b 8.7 – Inspect the ball bearings and replace if necessary, b 8.5.3

: Check the correct installed position of the piston rings again (arrows).

– Install the crankshaft, b 8.5.2 – Install the engine, b 8.4.2

217RA129 TG

– Install the piston, b 8.4.2

217RA130 TG

: Use a piece of old piston ring to scrape the grooves clean.

: Install the new piston rings in the grooves so that the radii at the ends of the rings (arrows) face towards the piston head.

MS 192 T

41

Ignition System

9.1

Exercise extreme caution while carrying out maintenance and repair work on the ignition system. The high voltages which occur can cause serious or fatal accidents.

Ignition Module

9.1.1

Removing and installing

1

1 2

217RA325 TG

Troubleshooting on the ignition system should always start with the spark plug, b 4.5 – Remove the fan cover, b 9.1.1

The ignition module accommodates all the components required to control ignition timing. There are two electrical connections on the coil body:

217RA087 TG

9.

: Take out the screws (arrows) and remove the fan housing (1) with rewind starter.

: High-voltage output (1) with permanently fitted ignition lead

1

: Connector tag (2) for the short circuit wire.

The electronic ignition system basically consists of an ignition module (1) and flywheel (2).

Ignition timing is fixed and cannot be adjusted during repair work. Since there is no mechanical wear in these systems, ignition timing cannot get out of adjustment during operation.

1

217RA008 TG

Testing in the workshop is limited to a spark test. A new ignition module with ignition lead must be installed if no ignition spark is obtained (after checking that the wiring and stop switch are in good condition), b 9.1.1

: Turn the twist lock (arrow) anticlockwise to release it and remove the carburetor box cover (1).

217RA009 TG

217RA097 TG

2

1 : Apply a suitable tool to the tab (arrow) to prise the boot off the spark plug (1).

42

MS 192 T

1

1

2

: Disconnect the short circuit line (1). : Remove the screw (arrow).

217RA100 TG

: Disconnect the ground wire (2).

217RA101 TG

: Remove the screw (arrow).

: Remove the cable guide (arrow).

MS 192 T

– Pull the ignition lead with spark plug boot out of the engine housing.

217RA096 TG

217RA102 TG

: Remove the ignition module (1) and cable guide (arrow) for the ignition lead (2).

: Slide the setting gauge (1) 4118 890 6401 between the arms of the ignition module and the magnet pole of the flywheel. – Press the ignition module against the setting gauge.

A damaged ignition lead can only be replaced together with the ignition module.

– Tighten down the screws.

– Examine the spark plug boot and replace it if necessary, b 9.4

– Reassemble remaining parts in reverse order.

– Tightening torques, b 3.5

– Reassemble parts in reverse order. – Moderately tighten the screws on the ignition module.

217RA098 TG

1

217RA099 TG

2

: Turn the flywheel until the magnet pole is lined up with the ignition module (arrow).

43

9.2

Ignition Timing

Ignition timing is fixed and cannot be adjusted during repair work. Since there is no mechanical wear in these systems, ignition timing cannot get out of adjustment during operation.

9.3

Testing the Ignition Module

To test the ignition module, use either the ZAT 4 ignition system tester 5910 850 4503 or the ZAT 3 ignition system tester 5910 850 4520.

The engine may start and accelerate during the test.

The ignition test refers only to a spark test, not to the ignition timing.

If no spark is visible in the window (2), check the ignition system with the aid of the troubleshooting chart, b 9.7

If a spark is visible, the ignition system is in order.

2

3

3

4

Using the ZAT 4 ignition system tester 5910 850 4503

Using the ZAT 3 ignition system tester 5910 850 4520

– Before starting the test, install a new spark plug in the cylinder and tighten it down firmly.

– Before starting the test, install a new spark plug and tighten it down firmly.

– Tightening torques, b 3.5

– Tightening torques, b 3.5

: Connect the spark plug boot to the input terminal (1). Push the tester's output terminal (3) onto the spark plug.

: Connect the spark plug boot to the terminal (2).

High voltage – risk of electrocution. : Crank the engine quickly with the rewind starter and check sparkover in the window (2) of the ignition system tester.

44

2

376RA134 TG

1

212RA209 VA

1

: Attach ground terminal (1) to the spark plug. : Use adjusting knob (4) to set the spark gap to approx. 2 mm, see window (3).

MS 192 T

9.4

Ignition Lead / Spark Plug Boot

The ignition lead cannot be replaced separately, as it is permanently connected to the ignition module.

5

– Remove the ignition module, b 9.1.1

34

212RA236 VA

2

376RA135 TG

1

: Use suitable pliers to pull the torsion spring out of the spark plug boot.

While using the ZAT 3, hold it only by the handle (4) or position it in a safe place. Keep fingers or other parts of your body at least 1 cm away from the spark window (3), high-voltage connection (2), ground connection (5) and the ground terminal (1).

– Unhook the torsion spring from the ignition lead. – Pull the boot off the ignition lead.

High voltage – risk of electrocution. – Crank the engine quickly with the rewind starter and check sparkover in the window (3) of the ignition system tester.

217RA094 TG

1

The engine may start and accelerate during the test. If a spark is visible, the ignition system is in order. If no spark is visible in the window (3), check the ignition system with the aid of the troubleshooting chart, b 9.7

: Pull the spark plug boot (1) with ignition lead (arrow) out of the engine housing towards the ignition module.

1 2

217RA326 TG

3

217RA095 TG

1

: Remove the cover (1) from spark plug boot.

– Examine the ignition lead (2), ignition module (3) and grommet (1) and replace if necessary. Ignition lead and ignition module can only be replaced as a complete unit.

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45

9.5

Flywheel

– Use a pointed tool to pierce the centre of the new lead's insulation about 15 mm from the end of the ignition lead.

: Ensure that the torsion spring engages in the opening (arrow).

217RA087 TG

217RA327 TG

1

Take out the screws (arrows) and remove the fan housing (1) with rewind starter. – Block the piston with the locking strip, b 6

217RA095 TG

376RA136 TG

: Pinch the hook of the torsion spring into the centre of the ignition lead (arrow).

: Slide the cover (1) over the spark plug boot.

: Remove the flywheel nut (arrow). – Remove the flywheel.

– Install the ignition module, b 9.1

376RA136 TG

– Reassemble remaining parts in reverse order.

– Coat the inside of the spark plug boot with STIHL Press Fluid, b 16 : Push the ignition lead and torsion spring into the spark plug boot.

Use the puller if the flywheel is stuck.

1

217RA090 TG

Do not use either graphite grease or silicone insulating paste.

46

217RA089 TG

1

1

Screw on the puller (1) 1116 893 0800, but do not screw it tight, and then tap the end of the puller lightly to release the flywheel.

MS 192 T

9.6 9.6.1 : Unscrew the puller (1) 1116 893 0800 from the crankshaft stub.

Short Circuit Wire Testing

– Reassemble parts in reverse order.

1

217RA328 TG

Degrease the crankshaft stub and bore in the flywheel hub with standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons.

Check the short circuit wire if the spark plug and ignition lead with spark plug boot are in order. – Remove the fan cover, b 8.4.1 : Disconnect the short circuit line (1).

1

– Connect the ohmmeter to ground (arrow) and the short circuit wire (1).

217RA091 TG

217RA093 TG

– Set the switch shaft to "0".

: Ensure that the machined key (arrow) engages the slot in the crankshaft.

: Remove the flywheel (1).

– Set the air gap between ignition coil and flywheel, b 9.1.1 – Reassemble remaining parts in reverse order.

217RA092 TG

– Tightening torques, b 3.5

Flywheel and magnet poles (arrows) must not show any signs of damage or blue discoloration, otherwise the flywheel must be replaced.

MS 192 T

The resistance measured must be about 0 W. If it is much higher, the reason is a break in the wire and it must be replaced, b 9.6 – Set the switch shaft to "#". The resistance measured must be infinitely high, otherwise fit a new short circuit wire, b 9.6 If no fault can be found, carry out further checks: – Check the flywheel, b 9.5 – Check the air gap between flywheel and ignition module, b 9.1.1 – If neither of these checks reveals a fault, install a new ignition module, b 9.1.1 – Reassemble parts in reverse order.

47

9.6.2

Removing and installing

– Remove fan housing, b 10.2

1

2

3

– Remove the handle moulding and actuating levers, b 12.1

: Remove the cable guide (arrow).

217RA329 TG

217RA101 TG

– Remove the switch shaft, b 12.3

: Examine the wiring harness (1), contact spring (2), contact spring (3) and grommets (arrows) and replace if necessary. For safety reasons, contact spring (3) may only be replaced together with the wiring harness.

: Remove the cover (1).

217RA320 TG

217RA103 TG

1

: Remove the cable guides (arrows).

2

: Take out the screw (arrow) and remove the ground wire (2). : Disconnect the short circuit line (1).

48

: Remove the contact springs (arrows) from the handle housing.

217RA319 TG

217RA318 TG

1

217RA099 TG

1

– Plug the contact spring (1) into the terminal socket of the wiring harness. : Place the contact springs in the guides (arrows).

MS 192 T

1

3

217RA166 TG

2

: Fit the switch shaft (1), pushing the rear contact spring (3) slightly to the side. Check operation: The contact springs are fitted in the handle housing at different depths. This means that the rear contact spring (3) and the front contact spring (2) must make contact with the metal pin of the switch shaft when the switch shaft (1) is in position "0". – Reassemble parts in reverse order. – Set the air gap between ignition coil and flywheel b 9.1.1 – Reassemble remaining parts in reverse order. – Tightening torques, b 3.5

MS 192 T

49

9.7

Troubleshooting, Ignition System

Engine does not run

Stop switch: – in position “#“?

Check spark plug: – Smeared with oil, black? – Sooted? – Electrode gap correct? – Contacts shorted? – Clean, adjust or replace the spark plug b 9.3

Check spark plug boot: – Firmly seated on spark plug (leg spring)? – Leg spring hook in centre of ignition lead? – Spark plug boot damaged? – Replace spark plug boot and/or leg spring if necessary b 9.4

Check ignition: with ZAT 3 or ZAT 4 (use ZAT 3 as main spark gap see TI 32.94) b 9.2 and b 9.3

1 50

MS 192 T

1

Spark present?

yes

no Air gap: – Check ignition module / flywheel, – Adjust if necessary, b 9.1.1

Check flywheel: – Have pole shoes turned blue? – Replace flywheel if necessary b 9.5

Check short circuit wire: – Replace short circuit wire if necessary b 9.6.1

Check ignition lead: – Severe chafing? – Spark plug boot: holes / cracks? – Resistance of spark plug boot to ground: required: 1.5...12 kW – Check resistance of ignition lead: value required < 10 W, – Replace spark plug boot and/or ignition lead with ignition module if necessary b 9.4

2 MS 192 T

3 51

2

3

Stop switch Check correct operation: – Short circuit wire chafed? – Contact springs not in contact with metal pin on switch shaft when in position "#"? – Replace short circuit wire if necessary b 9.6.2

Spark present?

yes

no Replace ignition module b 9.1.1

yes

Engine runs smoothly, troubleshooting procedure completed

52

Engine runs

no

– Look for fault in fuel or carburetor system – Check power unit for leaks – Check position of flywheel on crankshaft b 8.2, b 9.5

MS 192 T

Rewind starter General

If the action of the starter rope becomes very stiff and the rope rewinds very slowly or not completely, it may be assumed that the starter mechanism is in order but plugged with dirt. At very low outside temperatures, the lubricating oil on the rewind spring may thicken and cause the spring windings to stick together. This has a detrimental effect on the function of the starter mechanism. To clean the rewind spring, it is sufficient to apply a few drops of a standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons to the rewind spring. Carefully pull out the starter rope several times and allow it to rewind until its normal smooth action is restored.

10.2

Removing and Installing

– Tighten down the screws. – Tightening torques, b 3.5

: Take out the screws (arrows). – Remove the fan housing (1).

1

– Clean all components.

217RA281 TG

Before installing, lubricate the rewind spring and starter post with STIHL special lubricant, b 16 If clogged with dirt or pitch, the entire starter mechanism, including the rewind spring, must be removed and disassembled. Take particular care when removing the spring.

– Reassemble remaining parts in reverse order.

1

217RA087 TG

10. 10.1

: Press the locking lug (arrow) together slightly and remove the segment (1) from the fan housing. – Examine the fan housing and segment, replace if necessary.

217RA282 TG

1

: Fit the segment (1) in the slits (arrows) on the fan housing, then push it down until the segment engages.

MS 192 T

53

10.3

Pawls

10.4

Rope Rotor

– Remove fan housing, b 10.2 – Remove the spring, b 10.3

1

2

– Remove fan housing, b 10.2

: Remove the washer (1).

: Carefully ease the spring (1) off the starter post.

: Remove the pawl (2). Relieve tension of rewind spring

217RA250 TG

217RA283 TG

1

The rewind spring must be relieved.

: Remove the pawl (1). – Grease the pegs (arrow) of the new pawl, b 16 – Reassemble parts in reverse order.

217RA247 TG

217RA258 TG

217RA249 TG

1

: Pull out the starter rope about 5 cm and hold the rope rotor steady. – Still holding the rope rotor steady, take three full turns off the rope rotor. – Pull out the rope with the starter grip and carefully release the rope rotor. The system will not be under tension if the starter rope or rewind spring is broken.

: Carefully remove the rope rotor. – Remove the starter rope or remaining rope from the rope rotor. – Examine the rope rotor and replace it if necessary, – Remove any remaining rope from the fan housing if necessary. – Install a new starter rope, b 10.5 Lubricate the hole in the rope rotor with STIHL special lubricant oil, b 16

54

MS 192 T

10.5

Starter Rope / Grip

– Remove the fan housing, b 10.2

1

217RA248 TG

217RA251 TG

1

: Fit the rotor on the starter post so that the inner loop of the spring (arrow) enters the recess (1). The recess in the hub of the rope rotor acts as carrier for the spring loop. – Reassemble remaining parts in reverse order.

: Position the spring (1) so that the loop of the spring encloses the peg of the pawl and the curved part of the spring (arrow) is located in the groove in the starter post.

– Relieve the tension of the rewind spring and remove the rope rotor, b 10.4 The rewind spring will not be under tension if the starter rope is broken. – Remove any remaining scraps of rope from the rope rotor and starter grip.

– Then slide the straight part of the spring over the starter post until it engages in the groove.

– Grease the pegs of the pawls, b 16

982RA036 VA

– Tension the rewind spring, b 10.6

: Tie one of the two special knots shown above at the end of the rope in the starter grip.

MS 192 T

55

1

217RA356 TG

217RA353 TG

217RA255 TG

1

1

Machines with standard starter grip

Machines with ElastoStart starter grip

: Pull the rope (1) with spring and sleeve into the starter grip.

: Thread the new rope (1) through the side of the starter grip.

: Prise off the cap (1) with a suitable tool.

– Press the cap into the starter grip.

1

: Pull the rope out and continue threading it into the starter grip from the top.

217RA252 TG

217RA354 TG

217RA256 TG

1

: Pull the rope or remaining rope (1) out of the sleeve.

: Then thread the rope (1) through the opening (arrow).

1

: Pull the rope through the grip until the knot at the end of the rope is in the recess (arrow).

: Pull the rope (1) through the sleeve into the starter grip.

217RA253 TG

217RA355 TG

217RA257 TG

1

: Thread the rope (1) into the rope rotor (arrows).

– Tie a special knot in the end of the rope.

56

MS 192 T

10.6

Tensioning the Rewind Spring

1

1

217RA261 TG

217RA254 TG

217RA259 TG

2

: Secure the rope (1) with a simple overhand knot.

– Remove the fan housing, b 10.2

– Hold the starter grip firmly to keep the rope (1) tensioned.

– Pull the rope into the rope rotor until the knot rests in the recess (arrow) in the rope rotor.

: Pull out part of the rope (1) between rope rotor (2) and fan housing.

: Let go of the rope rotor and let the starter rope rewind slowly.

– Install the fan housing, b 10.2 – Tightening torques, b 3.5

: Turn the rope rotor with rope six times clockwise. The rope twists as the rope rotor and rope are turned. The rewind spring is now tensioned.

1

Hold the tensioned rope rotor firmly, as the rewind spring will be damaged if it jumps back suddenly.

217RA262 TG

– Install the rope rotor and tension the rewind spring, b 10.4

The rewind spring is correctly tensioned when the starter grip sits firmly in the rope guide bushing (arrow) without drooping to one side. If this is not the case, the spring must be tensioned by one additional turn. When the starter rope is fully extended, it must still be possible to rotate the rope rotor at least another half turn before the maximum spring tension is reached, otherwise the spring tension must be reduced – it may break –

2

217RA260 TG

1

To reduce the spring tension: Pull the rope out, hold the rope rotor steady and take off one turn of the rope.

– Hold the rope rotor (2) steady. : Pull out the rope (1) with the starter grip and straighten it out.

MS 192 T

– Install the fan housing, b 10.2 – Tightening torques, b 3.5

57

Replacing the Rewind Spring

– Troubleshooting, b 4.4 The replacement spring is supplied ready for installation and secured in a frame. Wear a face shield and protective gloves.

: Apply suitable tools (screwdriver, drift, etc.) to the recesses and push the spring into its seat in the housing – the spring slides out of the frame.

1

– Remove the frame. 217RA275 TG

10.7

The rewind spring may pop out. – Remove the fan housing, b 10.2 – Relieve the rewind spring if necessary and remove the rope rotor, b 10.4

– Arrange the spring (1) as shown in the illustration. : Position the anchor loop in the fixture (arrow).

– Remove any fragments of the old spring.

217RA276 TG

1

217RA284 TG

– Lubricate the spring with a few drops of STIHL special lubricant before installation, b 16

Ensure that the new rewind spring (1) is fitted completely and the anchor loop is positioned in the fixture (arrow).

1

: Hold the inserted loops securely to prevent them slipping out again.

217RA359 TG

If the rewind spring pops out during installation, fit it in the fan housing as follows:

: Fit the rewind spring (1) in a circular fashion, working in clockwise direction.

: Position the replacement spring with frame – the anchor loop must be located over the fixture (1).

58

MS 192 T

10.8

Starter Rope Guide Bushing

: Arrange the inner loop (arrow) with suitable pliers so that it is slightly angled against the starter post. – Install the rope rotor, b 10.4

1

– Remove the fan housing, b 10.2 – Relax the rewind spring and remove the starter rope and rope rotor, b 10.4

217RA279 TG

217RA277 TG

Wear on the guide bushing is accelerated by the starter rope being pulled sideways. The wall of the bushing eventually wears through and the bushing becomes loose.

: Insert the screw spindle (1) of the installing tool 0000 890 2201 through the guide bushing from inside the housing.

– Reassemble remaining parts in reverse order.

2 1 1 217RA278 TG

217RA280 TG

3

– Use a suitable tool to remove the damaged guide bushing from the fan housing. : Place the new guide bushing (1) in the hole in the fan housing.

: Fit the thrust sleeve (1) and hex nut (2). : Tighten down the hex nut, steadying the screw (3), until the bushing is firmly seated. The installing tool flares the lower end of the rope bushing. – Remove the installing tool. – Reassemble remaining parts in reverse order.

MS 192 T

59

Repairing the AV System

The handle housing and engine housing are connected by vibration damping rubber buffers and a spring. Damaged rubber buffers (annular buffers) and springs must be replaced.

11.1

Annular Buffer

The rubber buffer is located between handle housing and engine housing to secure the handle housing without transmitting vibrations. Remove the carburetor box cover, b 14.1

217RA309 TG

11.

Remove the sprocket cover and bar and chain, b 5.1 : Examine the rubber buffer and replace it if necessary. – Reassemble parts in reverse order.

217RA182 TG

– Tightening torques, b 3.5

217RA183 TG

: Remove the screw (arrow).

: Take out the screws (arrows). – Remove the rubber buffer.

60

MS 192 T

Front Handle / Spring

The spring is located between front handle and engine housing to ensure a strong connection between handle housing and engine housing without transmitting vibrations.

1

– Remove the throttle trigger and throttle trigger interlock, b 12.1 – Remove the switch shaft, b 12.3

217RA161 TG

1

– Open the handle housing, b 12.1

: Pull the front handle (1) out of the upper guide (arrow).

217RA164 TG

11.2

Ensure that the spring (1) has been fully turned into the front handle and bearing plug.

: Remove the screw (arrow).

: Draw the front handle out of the engine housing with the spring facing downwards.

217RA165 TG

217RA162 TG

217RA159 TG

– Reassemble parts in reverse order.

: Slide the front handle into the hole (arrow), ensuring that the raised parts of the handle engage the recess of the handle housing.

: Remove the screw (arrow) from underneath the engine housing.

2

: Examine the front handle (1), spring (2) and bearing plug (3) and replace if necessary.

217RA159 TG

1

217RA163 TG

217RA160 TG

3

: Insert and tighten down the screw (arrow). – Tightening torques, b 3.5 – Reassemble remaining parts in reverse order.

MS 192 T

61

11.3

AV Spring between Handle Housing / Engine Housing The AV spring is located between handle housing and engine housing to secure the handle housing without transmitting vibrations. The replacement spring is supplied complete with bearing plug.

11.4

To prevent the engine vibrating in the engine housing, a clamp is fitted on the inside of the engine housing so that the cylinder rests against the clamp. Remove the engine, b 8.4 217RA169 TG

– Remove the sprocket cover and bar and chain, b 5.1 – Open the handle housing, b 12.1

Clamp

– The following work is made easier by using STIHL Press Fluid, b 16

: Remove the screw (arrow).

: Remove the screw (arrow).

217RA184 TG

217RA170 TG

217RA168 TG

– Draw the AV spring out of the recess in the engine housing.

– Examine the AV spring and replace it if necessary,

: Press the rubber stub (arrow) out of the engine housing.

: Before installing the AV spring, ensure that it has been fully turned into the bearing plugs (arrows).

– Examine the clamp and replace it if necessary,

– Reassemble parts in reverse order.

1

: Prise off the bumper strip (1) with a suitable tool.

217RA185 TG

217RA172 TG

– Tightening torques, b 3.5

1 : Press the clamp (1) into the engine housing from below. – Reassemble remaining parts in reverse order.

62

MS 192 T

11.5

Loop

12. 12.1

Actuating Levers Throttle Trigger / Interlock Lever / Throttle Rod

: Remove the screw (arrow).

217RA241 TG

217RA237 TG

217RA186 TG

1

2 : Remove the interlock lever (1) and throttle trigger (2).

: Take out the screws (arrows).

1 1

– Examine the retaining plate and loop and replace them if necessary. : Fit the loop in the retaining plate (arrow) and position both parts on the engine housing.

217RA243 TG

217RA238 TG

217RA171 TG

2

: Carefully remove the handle moulding (1).

: Hook the torsion spring (1) into the throttle trigger (2). – note the installed position –

Throttle rod and actuating levers may drop out as the handle moulding is removed.

– Examine the torsion spring and replace it if necessary.

– Insert and tighten down the screw.

: Remove the throttle rod (1).

MS 192 T

217RA240 TG

1

217RA155 TG

– Tightening torques, b 3.5

: Place the torsion spring in the fixture (arrows).

63

12.2

2

217RA242 TG

1

Double Lever

– Tightening torques, b 3.5

– Remove the air filter, b 14.1

– Check correct functioning.

– Remove the air filter base, b 14.1.1 – Remove the handle moulding, throttle rod, interlock lever and throttle trigger, b 12.1 – Unhook the rod from the carburetor, b 14.2

: Fit the interlock lever and throttle trigger in the bearing guides (arrows).

217RA244 TG

217RA308 TG

When installing the interlock lever (1) and throttle trigger (2) ensure that the peg on the interlock lever engages in the guide (arrow).

1

: Remove the double lever (1) from the bearing hole (arrow).

: Push the throttle rod into the holes (arrows) on the throttle trigger and double lever. – Install the handle moulding, fit the screws and tighten them down securely. 64

2

217RA245 TG

217RA239 TG

1

: Install the double lever so that the throttle rod (1) can be fitted in the upper hole (arrow) and the throttle rod from the carburetor (2) in the lower hole (arrow).

MS 192 T

12.3

Switch Shaft

– Reassemble parts in reverse order.

1

– Tightening torques, b 3.5

217RA246 TG

– Check correct functioning.

Check operation The contact springs are fitted in the handle housing at different depths. The rear contact spring (3) and the front contact spring (2) must make contact with the metal pin of the switch shaft when the switch shaft (1) is in position "0". – Reassemble remaining parts in reverse order. – Tightening torques, b 3.5

– Remove the handle moulding, throttle rod, interlock lever and throttle trigger, b 12.1

– Check correct functioning again.

: Pull the switch shaft (1) out of the bearing.

217RA167 TG

1

: Check the switch shaft – the metal pin (1) must be firmly seated in the hole and the cam (arrow) must be present.

1

3

217RA166 TG

2

: Fit the switch shaft (1), pushing the rear contact spring (3) slightly to the side.

MS 192 T

65

12.4

Handle Housing

– Remove fan housing, b 10.2

1

– Remove the sprocket cover and bar and chain, b 5.1

The handle need not be dismantled when replacing the handle housing, as the handle housing is replaced as a complete unit – see spare parts list –

217RA172 TG

– Push the intake elbow on the carburetor side out of the handle housing, b 14.5

217RA101 TG

– Remove the carburetor, b 14.2

: Remove the bumper strip (1).

: Remove the cable guide (arrow).

: Remove the screw (arrow).

: Remove the cover (1).

217RA320 TG

217RA169 TG

217RA103 TG

1

: Remove the cable guides (arrows).

: Remove the screw (arrow).

66

217RA160 TG

1

217RA099 TG

217RA108 TG

2

: Take out the screw (arrow) and remove the ground wire (2).

– Disconnect the spring of the front handle from the engine housing.

: Remove the short circuit wire (1).

: Remove the screw (arrow).

MS 192 T

217RA299 TG

217RA337 TG

1

217RA162 TG

2

– Pull the front handle with handle housing down slightly.

: Disconnect the tank vent (1) from the fuel hose (2).

: Pull the bearing plug out of the engine housing.

– Draw the fuel hose (2) out through the opening (arrow).

: Unscrew the spring and bearing plug.

1

: Remove the tank vent (1).

: Push the grommet (1) out.

1 2

217RA336 TG

217RA181 TG

217RA316 TG

1

: Screw the spring (1) and bearing plug (2) into the new front handle. – Install the complete handle housing in the reverse sequence of steps. – Tightening torques, b 3.5

1

– Installation of rubber parts is made easier by using STIHL Press Fluid, b 16

: Push the fuel return line (1) out.

217RA298 TG

217RA300 TG

1

: Disconnect the impulse hose (1) from the stub (arrow). – Remove the handle housing.

MS 192 T

67

Chain Lubrication Pick-up Body

13.2

Impurities gradually clog the fine pores of the filter with minute particles of dirt. This prevents the oil pump from supplying sufficient oil to the bar and chain. Always check the oil tank and pick-up body first if problems develop in the oil supply. Clean the oil tank if necessary.

– Remove the clutch, b 6.1 – Remove the bumper strips, b 5.5

– Troubleshooting, b 4.3 – Unscrew the oil tank cap and drain the oil tank.

– Hold the suction hose with blunt pliers.

Collect chain oil in a clean container or dispose of it properly at an approved disposal site.

Oil Suction Hose

– Remove the sprocket cover and bar and chain, b 5.1

1

217RA188 TG

13. 13.1

– Unscrew the oil tank cap and drain the oil tank. – Remove the pick-up body, b 13.1

: Pull the pick-up body (1) off the suction hose.

– Flush out the oil tank.

217RA073 TG

217RA340 TG

1

: Take out the screws (arrows).

– Replace the pick-up body. : Push the pick-up body (1) into the suction hose and place it in the oil tank. – Reassemble remaining parts in reverse order.

2

1

: Use hook 5910 893 8800 to pull the pick-up body (1) out of the oil tank.

217RA074 TG

217RA187 TG

1

: Remove the cover (1), pulling the worm (2) off the crankshaft stub at the same time.

Take care not to overextend the suction hose.

68

MS 192 T

13.3

Oil Pump

: Pull the hose off the connector (arrow) on the oil pump.

217RA191 TG

217RA192 TG

Inadequate lubrication of the bar and chain may be due to the oil pump if the pick-up body, suction hose and valve have been checked and found to be in order.

: Use a suitable tool to press in the suction hose until the groove on the suction hose is lined up with the heel on the engine housing.

Remove the sprocket cover and bar and chain, b 5.1 Remove the clutch, b 6.1 Remove the bumper strips, b 5.5

: Pull the suction hose (1) out of the engine housing.

: Use hook 5910 893 8800 to pull the suction hose (1) out of the oil tank.

217RA340 TG

217RA190 TG

: Push the smaller diameter of the new suction hose (1) into the hole in the engine housing.

217RA073 TG

2

1

1

: Take out the screws (arrows).

: Push the pick-up body (1) into the suction hose and place it in the oil tank.

1

217RA074 TG

1

217RA077 TG

217RA189 TG

1

: Remove the cover (1), pulling the worm (2) off the crankshaft stub at the same time.

– Reassemble remaining parts in reverse order.

MS 192 T

69

13.4

Valve

Cleaning the valve

1

– Remove the sprocket cover and bar and chain, b 5.1

: Pull the hose off the connector (arrow) on the oil pump.

217RA341 TG

A valve is installed in the tank wall to keep internal tank pressure equal to atmospheric pressure.

217RA192 TG

2

– Remove the oil tank cap. – Drain the oil tank.

: Check the oil pump (1) and connector (2) and replace if necessary.

Collect chain oil in a clean container or dispose of it properly at an approved disposal site.

217RA345 TG

: Slip the oil pump (1) over the crankshaft stub and press the nipple on the connector as far as possible into the recess (arrow).

: Blow the valve (arrow) clear with compressed air (from outside to inside of tank).

217RA075 TG

217RA079 TG

1

: Remove the screw (arrow).

– Flush out the oil tank. – Reassemble remaining parts in reverse order.

1

– Grease the worm before installing it, b 16

2

– Tightening torques, b 3.5

– Reassemble parts in reverse order. The valve must be replaced if it still does not function properly after being cleaned.

217RA078 TG

Replacing the valve

: Remove the oil pump (1), pulling the connector (2) out of the recess in the engine housing.

70

– Remove the sprocket cover and bar and chain, b 5.1 – Remove the oil tank cap. – Drain the oil tank. Collect chain oil in a clean container or dispose of it properly at an approved disposal site.

MS 192 T

13.5

Oil Tank Filler Cap

: Remove the old valve from the oil tank.

217RA311 TG

: Lift up the safety latch and unscrew the tank filler cap (1).

: Fit a new valve in the hole a = approx. 8...10 mm.

217RA312 TG

217RA196 TG

: Carefully drive the valve out into the hole in the engine housing with a drift dia. 6 mm, working from the outside.

217RA339 TG

: Carefully drive the valve out of the tank wall into the tank with a drift dia. 6 mm.

217RA194 TG

217RA193 TG

1

: Prise the nipple out from inside the tank (arrow).

– Reassemble remaining parts in reverse order.

Ensure that the parts are installed correctly. : Carefully fit the valve in the hole in the engine housing.

MS 192 T

2

217RA313 TG

217RA195 TG

1

: Examine the filler cap (1), cord and sealing ring (2) and replace if necessary. The filler cap is supplied complete with cord and sealing ring.

71

14. 14.1

Fuel System Air Filter

Dirty air filters reduce engine power, increase fuel consumption and make starting more difficult.

1 217RA314 TG

217RA312 TG

The air filter should be checked when there is a noticeable loss of engine power. – Refer also to troubleshooting, b 4.7

: Press the nipple into the mount (arrow) inside the tank.

: Remove the air filter (1). – Knock out the filter or blow it clear with compressed air from the inside outwards.

– Screw in the filler cap. – Test for leaks.

1

217RA315 TG

217RA008 TG

1

: Turn the twist lock (arrow) anticlockwise.

: Take the foam inlay (1) out of the filter base.

– Remove the carburetor box cover (1).

– Clean away loose dirt from around the filter. Check the filter and foam inlay and replace them if damaged or dirty.

217RA330 TG

1

: Press the tabs (arrows) together and push the twist lock (1) out of the carburetor box cover.

72

– If soiled, wash all parts of the filter in STIHL universal cleaner or a fresh, non-flammable cleaning solution (e.g. warm soapy water) and allow to dry. Do not clean fleece (non-woven) filters with a brush. – Reassemble parts in reverse order.

MS 192 T

14.1.1 Air Filter Base

14.2

Carburetor, Removing and Installing

– Remove the air filter, b 14.1

1

2

217RA174 TG

217RA179 TG

– Remove the filter base, b 14.1.1

– Remove the air filter, b 14.1

When fitting the choke lever (1) on the choke shaft (2), ensure that the flat side of the choke shaft meshes with the semi-circular recess in the choke lever.

: Unscrew the nuts (arrows).

1

: Remove the filter base (1). – Examine the filter base and replace it if necessary, – Before installing the filter base, lubricate the sealing ring on the carburetor connector with STIHL Press Fluid, b 16

217RA181 TG

217RA180 TG

1

: Push out the grommet (1), examine it and replace it if necessary. – Reassemble parts in reverse order.

– Reassemble parts in reverse order.

: Pull the choke lever (1) off the choke shaft.

MS 192 T

217RA175 TG

1

1 217RA173 TG

Ensure that the air filter rests uniformly on the filter base all round.

: Disconnect the fuel hose (1) from the carburetor (arrow).

73

14.2.1 Leakage Test

: Carefully draw the carburetor off the fuel return line and stud bolts until the rods appear.

2

The carburetor can be tested for leaks with the carburetor and crankcase tester 1106 850 2905. – Disconnect the fuel hose from the carburetor and remove the carburetor, b 14.2

2

1

– Push the pressure hose of the tester 1106 850 2905 onto the double connector. : Close the vent screw (1) on the rubber bulb (2) and pump air into the carburetor until the pressure gauge (3) shows a reading of approx. 0.8 bar (80 kPa).

1

If this pressure remains constant, the carburetor is airtight. However, if the pressure drops, there are two possible causes:

217RA177 TG

143RA172 VA

1

: Unhook the rod (1) from the carburetor (arrow) and remove the carburetor.

3

249RA012 VA

217RA176 TG

The tank vent must also be checked and cleaned if problems develop with the carburetor or fuel supply, b 14.6.2

: Push the fuel line (1) 1110 141 8600 onto the double connector (2) 0000 855 9200.

1. The inlet valve is not sealing (impurities in the valve seat, sealing cone of the inlet needle is damaged or inlet control lever is sticking). Remove to clean, b 14.3.2 2. Metering diaphragm damaged, replace if necessary, b 14.3.1

– Reassemble parts in reverse order.

– After completing the test, open the vent screw (1) and pull the fuel line off the carburetor's elbow connector.

– Tightening torques, b 3.5 – Check correct functioning.

– Push the fuel hose onto the elbow connector.

217RA178 TG

– Install the carburetor, b 14.2 – Tightening torques, b 3.5 – Reassemble remaining parts in reverse order.

: Push the fuel line with double connector onto the fuel port (arrow).

74

MS 192 T

14.3 Carburetor Repair 14.3.1 Metering Diaphragm

– Examine the metering diaphragm for signs of damage and wear, replace the gasket.

– Remove the carburetor, b 14.2

217RA232 TG

217RA228 TG

The diaphragm material is subjected to continuous alternating stresses and eventually shows signs of fatigue. In other words, the diaphragm distorts and swells and must be replaced.

: Secure the gasket, metering diaphragm and end cover with two screws (arrows).

: Take out the screws (arrows).

2 1

: Remove the end cover (1).

– Note the order in which the metering diaphragm (2) and gasket (1) are installed.

If the gasket and diaphragm are stuck to the carburetor, they must be removed very carefully.

: Gasket and metering diaphragm must be aligned so that the tab (arrow) points towards the adjusting nozzles.

217RA233 TG

– Fit the remaining screws in the secured end cover and tighten down all screws, working crosswise.

2

217RA230 TG

1

217RA231 TG

217RA229 TG

1

: Carefully separate the metering diaphragm (1) and gasket (2).

MS 192 T

75

14.3.2 Inlet Needle

Ensure that the spring locates on the nipple of the inlet control lever. – Press the inlet control lever down and secure it with the screw.

212RA281 VA

217RA234 TG

– Check that the inlet control lever moves easily. – Install the metering diaphragm, b 14.3.1

: The sealing cone of the inlet needle must be replaced if a circular indentation (arrow) is visible on its tip.

– Remove the metering diaphragm, b 14.3.1 : Remove the screw (arrow).

2

: Pull the inlet control lever (1) with spindle (2) out of the groove in the inlet needle.

217RA219 TG

1

217RA235 TG

1

2 : Fit the inlet needle (1). : Fit spring (2) in bore.

The spring under the inlet control lever may pop out.

: Pull out the inlet needle (arrow). – Remove and examine the spring (1), replace it if necessary.

76

2 3

217RA220 TG

1

217RA236 TG

1

: Position the seat of the inlet control lever (1) with spindle (2) over the spring, then slide the fork of the inlet control lever into the groove in the inlet needle (1).

MS 192 T

14.3.3 Fixed Jet

14.3.4 Pump Diaphragm

: Unscrew the fixed jet (1) with a suitable screwdriver.

217RA222 TG

217RA221 TG

– Remove the metering diaphragm, b 14.3.1

– Remove the carburetor, b 14.2 : Remove the screw (arrow).

: Carefully separate the pump diaphragm (1) and gasket (2). The diaphragm material is subjected to continuous alternating stresses and eventually shows signs of fatigue. In other words, the diaphragm distorts and swells and must be replaced.

Take care not to damage the jet. – Examine the fixed jet and replace it if necessary.

2

217RA225 TG

1

1

1

– Examine the pump diaphragm for signs of damage and wear, replace the gasket.

217RA223 TG

– Reassemble parts in reverse order.

– Inspect the fuel strainer for contamination and damage, clean or replace it if necessary.

: Carefully remove the end cover (1).

: Carefully remove the gasket with pump diaphragm from the carburetor body.

217RA154 TG

217RA224 TG

1

: Pull the fuel strainer (1) out of the carburetor body with a needle and clean or replace it. – Reassemble parts in reverse order.

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77

14.3.5 Choke Shaft / Choke Shutter

: Fit the gasket (1) and secure it with the pegs (arrows).

: Turn the throttle shaft lever back and forth so that the end cover with stop pin (arrow) can be fitted without difficulty. – Gently move the end cover back and forth until the pegs on the end cover are lined up with the holes in the carburetor body. – Insert and tighten down the screw.

– Remove the carburetor, b 14.2 If actuation of the choke shaft is stiff and/or the choke shutter cannot be opened or closed properly: Remove the choke shaft, then clean the shaft and shaft guides with a little standard solvent-based degreasant not containing any chlorinated or halogenated hydrocarbons.

– Tightening torques, b 3.5

217RA227 TG

1

217RA266 TG

217RA199 TG

217RA226 TG

1

: Position the end cover on the carburetor body from below so that the gasket and pump diaphragm remain secured to the end cover.

78

217RA214 TG

217RA198 TG

: Place the diaphragm (1) over the gasket and secure it with the pegs (arrows).

: Remove the screw (arrow) from the choke shaft. The screw thread may be damaged when it is removed. – Use a new screw –

MS 192 T

217RA363 TG

: Turn the choke shaft anticlockwise with a suitable tool and remove the choke shutter (1).

: Examine the ball and spring and replace if necessary.

1

217RA217 TG

217RA346 TG

2 1

– Turn the choke shaft until the flat area is visible. : Fit the choke shutter (1) with the hole (2) at the front. .

1

1

3

: Pull out the choke shaft (1) and clean it with the guides. – Examine the choke shaft for signs of damage and replace it if necessary.

217RA218 TG

Take care that the ball and spring do not pop out when removing the choke shaft (1). – Wear safety glasses –

2 217RA215 TG

217RA216 TG

1

Ensure that the spring and ball are correctly fitted before installing the choke shaft.

The choke shutter (3) must be installed so that hole (1) is above and hole (2) axially parallel with the choke shaft.

: Slide the choke shaft (1) into the carburetor body until it engages.

– Secure the screw with Loctite, b 16 : Fit the new screw (arrow) in the shaft and tighten it moderately. – Close the choke shutter (3) and centre it in the bore of the carburetor body. – Tighten down the screw. – Check correct functioning and easy movement.

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79

14.3.6 Throttle Shaft / Throttle Shutter If actuation of the throttle shaft is stiff and/or the throttle shutter cannot be opened or closed properly:

: Remove the screw (arrow).

: Remove the circlip (arrow) with a suitable tool.

2

1

– Before pulling out the throttle shaft, secure the pump piston to prevent it popping out, b 14.3.7

: Turn the torsion spring (1) roughly a half-turn in clockwise direction with a suitable tool to prestress it.

: Unhook and relax the torsion spring (arrow).

– Push the pump piston into the bore of the carburetor with a suitable tool, b 14.3.7

217RA205 TG

1

: Pull the throttle shaft (1) with torsion spring out of the carburetor body.

1

: Install the torsion spring. Ensure that the torsion spring is fitted correctly (arrow).

217RA203 TG

217RA200 TG

– Remove the throttle shaft, then clean the shaft and shaft guides with a little standard solventbased degreasant not containing any chlorinated or halogenated hydrocarbons.

217RA202 TG

– Troubleshooting on the carburetor, b 4.6

217RA204 TG

– Remove the carburetor, b 14.2

: Push the throttle shaft (2) with prestressed torsion spring into the carburetor body.

217RA201 TG

– Clean the throttle shaft and guides.

– Turn the throttle shaft slightly.

– Examine the throttle shaft for signs of damage and replace it if necessary. – Examine the torsion spring and replace it if necessary.

: Pull out the throttle shutter (1).

80

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14.3.7 Accelerator Pump

1

: Position the prestressed torsion spring so that it rests against the shoulder (arrow) of the carburetor body.

: Insert the screw (1) in the flat side of the shaft and tighten it down moderately. – Close the throttle shutter (2) and centre it in the bore of the carburetor body.

217RA360 TG

217RA208 TG

217RA331 TG

2

– Remove the throttle shaft, b 14.3.6 Keep a finger over the hole (arrow) to prevent parts popping out.

The notch (arrow) on the throttle shutter must line up with the small bore in the carburetor body.

: Install the circlip.

– Check correct functioning and easy movement. – Secure the screw with Loctite, b 16

12

217RA361 TG

217RA206 TG

– Tighten down the screw.

3

– Examine the pump piston (1), sealing ring (2) and spring (3) and replace if necessary.

s

1

2

: Fit the throttle shutter (1) with the dent (3) on the left and the number (2) visible on the right.

217RA362 TG

217RA207 TG

3

Press the pump piston with spring into the hole (arrow) before installing the throttle shaft (1). – Reassemble remaining parts in reverse order.

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81

14.3.8 Adjusting screws

2

1

There are three adjusting screws on the carburetor: H = High speed screw (1) L = Low speed screw (2) LA = Idle speed screw (3)

: Examine the tip (arrow) for signs of damage or wear.

If the carburetor setting can no longer be adjusted, this may also be due to the adjusting screws.

– Reassemble parts in reverse order.

Only the high speed screw has a limiter cap; a new cap must always be used after dismantling the high speed screw.

217RA212 TG

3

217RA210 TG

217RA197 TG

1

: Take out the high speed screw (1).

– Replace the low speed screw if necessary.

– Adjust the low speed screw, b 14.4

217RA213 TG

Remove the carburetor, b 14.2 Refer also to troubleshooting on the carburetor, b 4.6

: Examine the tip (arrow) for signs of damage or wear. – Replace the high speed screw if necessary. High speed screw

Low speed screw

– Reassemble parts in reverse order.

1

: Take out the low speed screw (1).

217RA211 TG

217RA209 TG

1

– Adjust the high speed screw, b 14.4.1

: Prise the limiter cap (1) off the high speed screw with tool 5910 890 4501. Always fit a new limiter cap.

82

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14.4 Carburetor Adjustment 14.4.1 Basic Setting Only necessary if the high speed screw H or low speed screw L has to be replaced or for cleaning and setting the carburetor.

– Check air filter – clean or replace if necessary, b 14.1

– Remove the limiter cap from the high speed screw, b 14.3.8

– Check the spark arresting screen (if installed) – clean or replace if necessary, b 8.1 – Let the engine warm up. Set idle speed with a speed tester. Set the specified speeds within the tolerance range of ± 200 rpm. 1. Set the speed to 3500 rpm with the idle speed adjusting screw LA.

1

2. Turn the low speed screw L clockwise or anticlockwise to set the highest speed.

2

1

217RA347 TG

The basic setting must be made after removing the limiter cap.

– Check the chain tension.

Always use a new limiter cap. Before fitting the limiter cap, it must be positioned so that the raised part (1) is below the stop (arrow) on the carburetor body. Then press the limiter cap onto the preset high speed screw. : Press the limiter cap onto the high speed screw H.

217RA332 TG

If this speed is more than 3900 rpm, stop the adjustment and start again with step 1. 3. Set the speed to 3500 rpm again with the idle speed adjusting screw LA.

: Turn the high speed screw H (1) clockwise until it is firmly in its seat.

4. Set the speed to 3000 rpm with the low speed screw L.

: Turn the high speed screw H (1) anticlockwise until it is one turn open. : Turn the low speed screw L (2) clockwise until it is firmly in its seat.

5. Set the maximum speed of 13,500 rpm with the high speed screw H. 6. Fit the limiter cap.

: Turn the low speed screw L (2) anticlockwise until it is one turn open.

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83

14.4.2 User Setting

Engine stops when idling

Erratic idling behaviour, poor acceleration

– Make standard setting!

217RA334 TG

– Make standard setting! – Turn the idle speed screw LA clockwise until the saw chain begins to run, then back off 1/4 turn.

Idle setting too lean (e.g. at low ambient temperatures).

Saw chain rotates at idle speed

– Turn the low speed screw L anticlockwise until the engine runs and accelerates smoothly.

– Make standard setting! The limiter cap must not be removed from the high speed screw when making the user setting. Standard setting

– Turn the idle speed screw LA anticlockwise until the saw chain stops, then give it another 1/4 turn in the same direction.

It is usually necessary to change the setting of the idle speed adjusting screw LA after every correction to the low speed adjusting screw L.

– Switch off engine – Check the air filter – clean or replace if necessary, b 14.1 – Check the chain tension. – Check the spark arresting screen (if installed) – clean or replace if necessary, b 8.1 – Carefully turn the high speed screw H anticlockwise as far as possible (max. 3/4 turn). – Carefully turn the low speed screw L clockwise until it is firmly in its seat. Then open it one turn.

84

MS 192 T

14.5

The setting may have to be marginally corrected if the engine performance is unsatisfactory at high altitudes. – Check the standard setting. – Let the engine warm up. – Turn the high speed screw H clockwise (leaner) – max. up to the stop.

– Remove the air filter, b 14.1

1

– Remove the filter base, b 14.1.1 – Remove the carburetor, b 14.2 – Unscrew the rubber buffers, b 11.2

217RA264 TG

Correcting the carburetor setting for use at high altitudes

Intake Elbow, Removing and Installing

A damaged intake elbow may lead to impaired engine performance. – Troubleshooting, b 4.6 or b 4.7

: Remove the washer (1).

The screws should be adjusted as little as possible. The slightest adjustment produces a tangible difference in engine behaviour.

1

If you make the setting too lean it will increase the risk of engine damage through lack of lubrication and overheating.

217RA265 TG

1 217RA107 TG

If the adjustments do not yield any improvement, refer also to the troubleshooting chart for ignition system, carburetor and power unit, b 4.6

: Prise off the supporting plate (1) with a suitable tool.

: Take the sleeve (1) out of the intake elbow. – Press the flange of the intake elbow out through the hole in the handle housing towards the cylinder. – Examine the intake elbow and replace it if necessary.

217RA358 TG

1

: Lift the handle housing and pull the elbow (1) off the cylinder.

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85

The tab on the elbow flange must not cover the opening in the handle housing otherwise the impulse hose will not operate correctly.

217RA267 TG

217RA269 TG

1

: Before installing the intake elbow, slide the supporting plate onto the elbow so that the rebate (arrow) and tab (1) face the carburetor.

: Draw the ends of the string through the intake port with the elbow flange. – Coat with STIHL Press Fluid, b 16 In this way, the elbow flange is fitted through the intake port of the tank housing without damaging it.

1 217RA263 TG

217RA268 TG

1

: Push the elbow (1) onto the intake port (arrow).

: To draw the elbow flange into the intake port of the tank housing, wrap a piece of string (1) approx. 15 cm long round the elbow and guide the ends of the string through the intake port. – Position the elbow on the handle housing.

– Ensure that the flange is correctly seated in the handle housing.

217RA271 TG

217RA270 TG

1

: Ensure that the elbow (1) completely encloses the intake port.

The tab on the elbow flange (arrow) must be aligned so that the hole is lined up with the opening in the handle housing. 86

MS 192 T

14.5.1 Impulse Hose

1

217RA104 TG

: Fit the supporting plate (1) so that the tab (arrow) points upwards and towards the chain.

217RA335 TG

217RA272 TG

1

A damaged impulse hose may lead to impaired engine performance.

: Disconnect the impulse hose (1) from the stub (arrow).

– Remove the fan housing, b 10.2

– Pull the impulse hose out of the engine housing.

– Remove the flywheel, b 9.5

– Examine the impulse hose and replace it if necessary,

– Unscrew the rubber buffers on the handle housing, b 11.1 – Remove the carburetor, b 14.2

217RA273 TG

– Push the intake elbow out of the handle housing, b 14.5

: Press the supporting plate home completely until it rests against the engine housing all round (arrows).

– Troubleshooting, b 4.6 or b 4.7

When installing the impulse hose, ensure that the spring is actually in the hose to prevent it buckling. – Lubricate the ends of the impulse hose with STIHL Press Fluid, b 16

The impulse hose is shown on the handle housing after disassembly for clarity.

– Reassemble remaining parts in reverse order. – Tightening torques, b 3.5

1

: Disconnect the impulse hose (1) from the stub (arrow) of the handle housing.

MS 192 T

217RA348 TG

217RA298 TG

1

: Guide the impulse hose (1) through the opening (arrow) on the engine housing and push it onto the stub on the handle housing.

87

14.6 Tank Vent 14.6.1 Testing A pressure equilibrium must always prevail between the inside of the fuel tank and the surrounding atmosphere to permit troublefree operation of the carburetor. This is ensured by the tank vent.

: Connect the impulse hose (1) to the stub (arrow). – Reassemble remaining parts in reverse order.

If problems develop in the carburetor or fuel supply, the tank vent must always also be tested and replaced if necessary. Correct functioning is determined by testing the fuel tank with negative pressure or gauge pressure via the fuel hose. – Remove the fan housing, b 10.2

2

217RA342 TG

217RA157 TG

1

1

: Disconnect the fuel return line (1) and push the double nipple (2) 0000 855 9200 into the flange (arrow) of the suction hose.

– Drain the fuel tank. Ensure that the impulse hose is routed correctly and without kinking.

Ensure that the fuel is disposed of correctly and without harming the environment.

2 0,4 0,6 400 500

0,8

600

300

0,2

200 100

700

0

217RA344 TG

1,0

1 Testing with negative pressure

: Close the valve (1) and connect the vacuum pump (2) 0000 850 3501 to the double nipple, then create a vacuum in the fuel tank. Pressure is equalized via the tank vent. A negative pressure must not build up inside the tank. The tank vent must be replaced if this is not the case.

217RA103 TG

1

: Remove the cover (1).

88

– Clean the area around the tank vent. – Replace the tank vent or tank if necessary, b 14.6.2 or b 14.8.3

MS 192 T

14.6.2 Removing and Installing

1

146RA063 VA

217RA316 TG

1

Testing with gauge pressure

– Remove the air filter, b 14.1

: Close the vent screw (1).

– Remove the filter base, b 14.1.1

14.7 Fuel Intake 14.7.1 Pick-up Body Impurities which are entrained into the fuel tank with the fuel are trapped by the pick-up body. With time, the fine pores in the pick-up body become clogged with very fine dirt particles. This reduces the intake diameter and fuel can no longer be delivered in sufficient quantities. Always check the fuel tank and pickup body first if problems develop in the fuel supply. Clean the fuel tank if necessary.

: Pull the tank vent (1) out of the holder on the handle housing.

1 0,4 0,2 0

0,6

1

0,8 1,0

217RA317 TG

: Connect the carburetor and crankcase tester 1106 850 2905 (1) to the double nipple (arrow).

: Disconnect the tank vent (1) from the hose (2).

– Pump the rubber bulb until the reading on the pressure gauge shows an excess pressure of 0.5 bar. If this pressure remains constant for at least 20 seconds, the tank and tank vent are airtight. If the pressure drops, the leak must be located and the faulty part replaced. – Reassemble parts in reverse order.

– Examine the tank vent and replace it if necessary, – Reassemble parts in reverse order.

217RA295 TG

217RA343 TG

2

: Lift up the safety latch, remove the filler cap (1) and drain the tank. – Fill a little clean petrol into the tank, close the tank and shake it thoroughly. – Reopen the tank and empty it. Ensure that the fuel is disposed of correctly and without harming the environment. If cleaning the tank does not remedy the problem, clean the pick-up body or replace it if necessary. – Troubleshooting, b 4.6 or b 4.7

MS 192 T

89

14.8

Remove the air filter, b 14.1

1

1

Fuel Hoses

Remove the fan cover, b 9.1

: Use hook 5910 893 8800 to pull the pick-up body (1) out of the fuel tank. Take care not to overextend the fuel hose.

: Push the pick-up body (1) into the tank filler port. – The pick-up body should be positioned at the lowest point inside the tank. – Reassemble remaining parts in reverse order.

1

: Disconnect the pick-up body (1) from the fuel hose (2).

217RA103 TG

2

217RA286 TG

1

217RA292 TG

217RA285 TG

Remove the intake elbow, b 14.5

: Remove the cover (1).

– Check the pick-up body and clean or replace it if necessary.

: Slide the connectors of the cleaned or replaced pick-up body (1) into the fuel hose (2).

90

217RA300 TG

1

2

217RA291 TG

1

: Push the fuel return line (1) out.

MS 192 T

1

1 3

1 217RA287 TG

: Pull the fuel return line (1) out of the guides and flange (arrow).

217RA307 TG

217RA302 TG

3

: Pull the elbow connectors (3) off the hoses.

: Pull the fuel suction hose (1) out of the tank.

– Check the fuel hose (1), fuel return line (2) and elbow connectors (3) and replace them if necessary.

– Examine the fuel suction hose and replace it if necessary,

2

– Reassemble parts in reverse order.

217RA288 TG

1

217RA349 TG

1

: Pull the fuel hose (1) out of the hose on the fuel pump.

: Push the fuel suction hose (1) into the hole in the fuel tank.

1

: Pull the fuel hose (1) out of the guides and flange (arrow).

– Remove the pick-up body, b 14.7.1 : Prise off the flange (1) with a suitable tool.

MS 192 T

1 217RA289 TG

217RA293 TG

217RA303 TG

1

: Align the flange (1) and press it into the fixture on the housing until it rests against the housing.

91

14.8.1 Fuel Pump

1 1

217RA317 TG

: Use hook 5910 893 8800 to pull the fuel suction hose (1) out of the fuel tank.

: Disconnect the tank vent (1) from the hose (2).

Take care not to overextend the fuel hose.

– Pull the hose (2) out through the opening in the handle housing.

217RA304 TG

217RA290 TG

2 1 – Remove the air filter, b 14.1 – Remove the fan housing, b 10.2 : Disconnect the fuel hose (1).

– Fit the pick-up body, b 14.7.1 – Reassemble remaining parts in reverse order.

: Disconnect the fuel hose (1) from the fuel pump.

: Disconnect fuel hose (1) and examine fuel hose (2), replace if necessary. – Reassemble parts in reverse order.

92

217RA306 TG

1

217RA316 TG

: Remove the tank vent (1).

: Press the tabs (arrows) together and push the fuel pump (1) out of the housing.

217RA301 TG

2

1

217RA305 TG

1

217RA304 TG

1

: Examine the fuel pump and replace it if necessary, – Reassemble parts in reverse order.

MS 192 T

14.8.2 Fuel Tank Filler Cap

14.8.3 Tank Housing, Removing and Installing The tank housing is integrated into the engine housing. The complete engine housing must always be replaced if the fuel tank, oil tank or engine housing is damaged.

: Lift up the safety latch and unscrew the tank filler cap (1).

217RA310 TG

217RA295 TG

1

: Press the nipple into the mount (arrow) inside the tank. – Screw in the filler cap. – Test for leaks.

217RA296 TG

– Reassemble remaining parts in reverse order.

1

2

217RA297 TG

: Prise the nipple out from inside the tank (arrow).

: Examine the filler cap (1), cord and sealing ring (2) and replace if necessary. The filler cap is supplied with cord and sealing ring; the sealing ring is available separately. MS 192 T

93

15.

Special Servicing Tools

No.

Part name

Part No.

Use

1 2 4 5 6 7

Locking strip Sealing plate Strap retainer Flange Assembly tool Carburetor and crankcase tester

0000 893 5903 0000 855 8106 1137 893 2600 1128 850 4200 0000 890 2201 1106 850 2905

8 9 10 11 12 15 16 17 19 20

Vacuum pump - Connector - Hose for leakage test Puller Puller (with No. 3.1 jaws) Press sleeve Assembly tube Assembly hook Assembly tool 10 Setting gauge

0000 850 3501 0000 855 9200 1110 141 8600 5910 890 4501 5910 890 4400 4112 893 2401 1117 890 0900 5910 890 2800 5910 890 2210 4118 890 6401

21 22 23

Assembly hook Assembly stand Clamping strip for assembly stand Puller Ignition system tester ZAT 4 Ignition system tester ZAT 3

5910 893 8800 5910 890 3100 5910 890 2000

Block crankshaft Seal exhaust bore Tension the piston rings Leakage testing Flare the starter rope guide bushing Test crankcase and carburetor for leaks Test crankcase for leaks, test tank vent Test carburetor for leaks Test carburetor for leaks Remove limiter cap Remove oil seals Press in oil seal Hook in clutch spring Detach springs from clutch shoes Fit hookless snap rings in piston Set the air gap between ignition module and flywheel Remove pick-up body Hold chainsaw for servicing / repairs Clamp machine to assembly stand

1116 893 0800 5910 850 4503 5910 850 4520

Remove flywheel Test ignition system Test ignition system

25 27 28

94

Rem.

MS 192 T

No.

Part name

Part No.

Use

29 30 31 33 35

Torque wrench Torque wrench Bit size 13 Combination wrench Bit T 27 x 125

5910 890 0302 5910 890 0312 5910 893 5608 1129 890 3401 0812 542 2104

35

Bit T 20 x 125

0812 542 2041

Screw connections (0.5 to 18 Nm) Screw connections (6 to 80 Nm) Crankshaft nut Spark plug Remove and install spline socket head screws with electric or pneumatic screwdrivers; tighten down screws with torque wrench Remove and install spline socket head screws with electric or pneumatic screwdrivers; tighten down screws with torque wrench

36 37 38 41 42

Screwdriver T 20 x 100 Screwdriver Q-SW8x200 Stud puller Crimping pliers Assembly pin

5910 890 2301 5910 890 2420 5910 893 0501 5910 890 8210 1114 893 4700

Carburetor nuts Remove rail mounting studs Cable ties, cable lugs, etc. Remove and install the piston pin

Rem.

1)

1) 1)

Remarks: 1) Use only for releasing.

MS 192 T

95

16.

Servicing Aids

No.

Part name

Part No.

Use

1

Lubricating grease (225 g tube)

0781 120 1111

Oil seals, sliding and bearing points

2

STIHL special lubricant

0781 417 1315

Bearing bore in rope rotor, rewind spring in fan housing

3

Press Fluid OH 723

0781 957 9000

Rubber buffers in AV system

4

STIHL multi-purpose grease

0781 120 1109

High-voltage output on ignition module

5

Dirko HT red sealant

0783 830 2000

Engine pan, oil seals (outside)

6

High-strength thread-locking adhesive (Loctite 270)

0786 111 2109

7

Standard commercial solventbased degreasant containing no chlorinated or hydrogenated hydrocarbons

96

Cleaning sealing faces and the carburetor, cleaning the crankshaft stub and tapers in flywheel

MS 192 T

englisch / english 0455 217 0123. M5. B5. T. Printed in Germany