STIHL MS 192 T€¦ · STIHL parts symbol (The symbol may appear alone on small parts. 1....

STIH)

STIHL MS 192 T 20 05-0 2

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q© ANDREAS STIHL AG & Co. KG, 2005

Contents

1. Introduction 3

2. Safety Precautions 4

3. Specifications 5

3.1 Engine 53.2 Fuel System 53.3 Ignition System 53.4 Chain Lubrication 53.5 Tightening Torques 6

4. Troubleshooting 8

4.1 Clutch 84.2 Chain Drive,

Chain Brake, Chain Tensioner 9

4.3 Chain Lubrication 104.4 Rewind Starter 114.5 Ignition System 124.6 Carburetor 134.7 Engine 15

5. Chain/ Spiked Bumper 16

5.1 Chain and Chain Guide 16

5.2 Tensioning the Chain 175.3 Chain Catcher 175.4 Bumper Spike 175.5 Bumper Strips 18

6. Clutch 18

6.1 Sprocket / Clutch Drum 20

7. Checking Operation of Chain Brake 21

7.1 Removing and Installing 21

7.2 Chain Tensioner 257.3 Bar Mounting Stud 26

MS 192 T

8. Engine 27

8.1 Muffler / Spark Arresting Screen 27

8.2 Leakage test 278.2.1 Preparations 288.2.2 Vacuum test 288.2.3 Pressure test 298.3 Oil Seals 308.4 Engine 318.4.1 Removal 318.4.2 Installation 328.5 Crankshaft 348.5.1 Removal 348.5.2 Installation 358.5.3 Crankshaft / Bearing 378.6 Piston 398.6.1 Removal 398.6.2 Installation 398.7 Piston rings 41

9. Ignition System 42

9.1 Ignition Module 429.1.1 Removing and

installing 429.2 Ignition Timing 449.3 Testing the Ignition

Module 449.4 Ignition Lead /

Spark Plug Boot 459.5 Flywheel 469.6 Short Circuit Wire 479.6.1 Testing 479.6.2 Removing and

installing 489.7 Troubleshooting,

Ignition System 50

10. Rewind starter 53

10.1 General 5310.2 Removing and

Installing 5310.3 Pawls 5410.4 Rope Rotor 5410.5 Starter Rope / Grip 5510.6 Tensioning the Rewind

Spring 5710.7 Replacing the Rewind

Spring 5810.8 Starter Rope Guide

Bushing 59

11. Repairing the AV System 60

11.1 Annular Buffer 6011.2 Front Handle / Spring 6111.3 AV Spring between

Handle Housing / Engine Housing 62

11.4 Clamp 6211.5 Loop 63

12. Actuating Levers 63

12.1 Throttle Trigger / Interlock Lever / Throttle Rod 63

12.2 Double Lever 6412.3 Switch Shaft 6512.4 Handle Housing 66

13. Chain Lubrication 68

13.1 Pick-up Body 6813.2 Oil Suction Hose 6813.3 Oil Pump 6913.4 Valve 7013.5 Oil Tank Filler Cap 71

1

Contents

14. Fuel System 72

14.1 Air Filter 7214.1.1 Air Filter Base 7314.2 Carburetor, Removing

and Installing 7314.2.1 Leakage Test 7414.3 Carburetor Repair 7514.3.1 Metering Diaphragm 7514.3.2 Inlet Needle 7614.3.3 Fixed Jet 7714.3.4 Pump Diaphragm 7714.3.5 Choke Shaft / Choke

Shutter 7814.3.6 Throttle Shaft /

Throttle Shutter 8014.3.7 Accelerator Pump 8114.3.8 Adjusting screws 8214.4 Carburetor

Adjustment 8314.4.1 Basic Setting 8314.4.2 User Setting 8414.5 Intake Elbow,

Removing and Installing 85

14.5.1 Impulse Hose 8714.6 Tank Vent 8814.6.1 Testing 8814.6.2 Removing and

Installing 8914.7 Fuel Intake 8914.7.1 Pick-up Body 8914.8 Fuel Hoses 9014.8.1 Fuel Pump 9214.8.2 Fuel Tank Filler Cap 9314.8.3 Tank Housing,

Removing and Installing 93

15. Special Servicing Tools 94

16. Servicing Aids 96

2

MS 192 T

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.

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.

MS 192 T

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:

A Item pointer (short)

aDirection 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.

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

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12

3

1

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 numberSTIH) logoand theSTIHL parts symbol (The symbol may appear alone on small parts.

1. Introduction

3

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

2. Safety Precautions

MS 192 T

3. Specifications

3.1 Engine

MS 192 T

Displacement: 30.1 cm3

Bore: 37 mmStroke: 28 mmEngine power to ISO 7293 1.3 kW (1.8 HP)

at 9500 rpmMax. permissible engine speed(with bar and chain): 13500 rpmIdle speed: 3000 rpmClutch: Centrifugal clutch without liningsClutch engages at: 4150 rpmCrankcase leakage testat gauge pressure: 0.5 bar under vacuum 0.5 bar

3.2 Fuel System

Carburetor leakage test at gauge pressure: 0.8 bar Operation of tank vent at gauge pressure: 0.3 bar Fuel: as specified in instruction

manual

3.3 Ignition System

Air gap between ignition module and fanwheel: 0.15...0.35 mmSpark plug (suppressed): NGK BPMR 7 AElectrode gap: 0.5 mm

3.4 Chain Lubrication

Fully automatic, speed-controlled oil pump with rotary piston

Oil delivery rate: 6.5 - 8.5 cm³ at 10,000 rpm

5MS 192 T

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 Tighteningtorque

Remarks

Nm

Screw DG 4x15 Chain tensioner cover plate / engine housing

2,5

Screw D 6x13 Collar screw for guide bar, rear 6,0Collar screw DG 8x18 Collar screw for guide bar, front 16,0Screw B 4.2x9.5 Cover plate/ screen/ muffler 2,0Screw P 4x12 Cover/ sprocket cover/ engine housing

tensioner2,5

Nut M 5 Filter base/ handle housing, 1st stage aluminium

1,5

Nut M 5 Filter base/ handle housing, 1st stage 2,0Nut M 5 Filter base/ handle housing, 2nd stage

aluminium2,5

Nut M 5 Filter base/ handle housing, 2nd stage 3,5Screw P 6x19 Handle housing/ front handle 6,0Screw P 4x12 Handle moulding/ handle housing 1,5Screw P 6x19 Retaining plate/ loop/ engine housing 6,0Screw DG 5x20 Engine pan/ cylinder 8,0Screw P 5x16 Bearing plug/ handle housing 4,0Screw P 5x16 Bearing plug/ engine housing, sprocket

side4,0

Screw P 5x16 Bearing plug/ engine housing, fan side 4,0Screw P 5x16 Fan housing/ engine housing 4,0

M 8x1 L Carrier 25,0Screw DG 5x20Z Engine housing/ cylinder 8,0Screw DG 4x20 Oil pump/ engine pan 4,5Screw P 4x12 Annular buffer, support/ engine housing 2,5Screw P 5x29.6 Annular buffer/ handle housing 5,0Screw DG 5x20 Muffler / cylinder 9,0Nut M 8X1 Flywheel/ crankshaft 18,0

M 14x1.25 Spark plug 25,0Screw DG 4x20 Ignition module/ cylinder 4,5

6 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.

7MS 192 T

4. Troubleshooting4.1 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

Saw chain rotates at idle speed Idle speed too high Readjust with idle speed screw LA (anticlockwise)

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

Clutch spring hooks broken Replace clutch springs

Loud noises 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

8 MS 192 T

4.2 Chain Drive, Chain Brake, Chain Tensioner


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

Saw chain stops under load at full throttle

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

Saw chain rotates at idle speed Idle speed too high Readjust with idle speed screw LA (anticlockwise)

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

Clutch spring hooks broken Replace clutch springs

Saw chain does not stop immediately when brake is activated

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

9MS 192 T

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.

.


Chain receives no oil Oil tank empty Fill up with oil

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

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

Machine losing chain oil Oil pump housing defective Replace oil pump

Oil pump damaged or worn Replace oil pump

Oil pump delivers insufficient oil Oil pump worn Replace oil pump

10 MS 192 T

4.4 Rewind Starter


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

Starter rope does not rewind 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 rope is difficult to pull and rewinds very slowly

Starter mechanism is very dirty Thoroughly clean complete starter mechanism

11MS 192 T

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.


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

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


Weak magnetization in flywheel – pole shoes have turned blue


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

Crankcase damaged (cracks) Replace crankcase

12 MS 192 T

13MS 192 T

4.6 Carburetor


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

Poor acceleration 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

14 MS 192 T


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

Engine stops when idling 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

Engine speed drops quickly under load – low power

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

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


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

Engine does not deliver full power or runs erratically

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

Engine overheating 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

15MS 192 T

Wear protective gloves– risk of injury –

: Disengage the chain brake by pulling the hand guard (1) towards the front handle until it engages.

1

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G

: Unscrew the hex nut (arrow).

: Turn the screw anticlockwise to relax the chain.

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A00

4 T

G

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

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G

1

16

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

– Remove the guide bar (1).

– Remove the chain (2) via the sprocket.

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G

1

2

– Reassemble parts in reverse order.

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

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G

– Reassemble remaining parts in reverse order.

– Tension the chain, b 5.2

– Tightening torques, b 3.5

5. Chain/ Spiked Bumper5.1 Chain and Chain Guide

MS 192 T

: Turn the screw clockwise to tension the chain.

: Tighten the hex nut (arrow).21

7RA

076

TG

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.

If the chain is tensioned

1

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G

excessively, this may result in

damage to the chain, guide bar and sprocket, as well as its needle bearing.

MS 192 T

Sprocket cover with integrally moulded chain catcher (1).

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

1

2

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G

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

: Remove the screw (arrow).

: Remove the chain catcher (3).

– Reassemble parts in reverse

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G

3

order.


– Remove the chain catcher,b 5.3


1

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G

: Remove the spiked bumper (1).


5.2 Tensioning the Chain
5.3 Chain Catcher 5.4 Bumper Spike
17

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

Worn bumper strips must be replaced, otherwise the engine housing may be damaged.

Remove the sprocket cover and bar and chain, b 5.1

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

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G

1

1

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


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G

18

– Troubleshooting, b 4.1


: Release the twist lock (arrow).

: Remove carburetor box cover (1) to the rear.

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G

1

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

1 217R

A00

9 T

G

: Unscrew the spark plug (1).

1

217R

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G

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

1

217R

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G

: Unscrew the clutch (1).

The clutch has a left-hand thread.

1

217R

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G

5.5 Bumper Strips
6. Clutch
MS 192 T

Disassembly

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

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G

21

– Pull the clutch shoes off the carrier.

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

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G

1

– Clean all parts.

– Replace any damaged parts.

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G

MS 192 T

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

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G

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).

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A01

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G

1 2

: Clamp the clutch in a vice (arrow).

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G

: 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.

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9 T

G

1

2

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.

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G

1137

1137

1137

19

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

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G

: 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

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1

cylinder.


20

– Remove the clutch, b 6

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

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G

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.

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1

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

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

VA

148R

A10

1

80%

100%

1

!

original thickness remain.


– Grease the needle cage and crankshaft stub, b 16

: Slip the needle cage (1) onto the crankshaft stub.

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1

6.1 Sprocket / Clutch Drum

MS 192 T

: Slip sprocket (1) onto crankshaft stub.

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1

The sprocket must engage the studs (arrow) of the wormwheel.


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MS 192 T

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.

– Start the engine.

– 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.

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

Removal



: Engage the chain brake by

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1

pushing the hand guard (1)

downwards.

The brake spring of the brake band is now relaxed.

: Take out the screws (arrows).

217R

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G

7. Checking Operation of Chain Brake

7.1 Removing and Installing

21

: Remove the cover (1).

1

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A02

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G

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

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

12

217R

A02

8 T

G

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

1

217R

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G

22

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.

217R

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G

: Remove the E-clip (arrow).

217R

A03

0 T

G

: Remove the hand guard (2) with lever (1) from the pivot pins.

– Pull the lever out of the hand guard.

217R

A03

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2

1

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

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

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

217R

A03

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G

1 2

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

MS 192 T

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

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

217R

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1

: Place the leaf spring (1) in the opening (arrow).

– Lightly grease both the leaf spring and the pin of the inlay.

The anchor pin must be replaced if the groove in the brake spring

1

217R

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anchor pin is worn. Proceed as

follows:

MS 192 T

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

1

217R

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– 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

1

217R

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back and forth as necessary.

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

The pin must be driven in squarely.

217R

A32

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a

1

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

– Check the bumper strip and replace it if necessary.


217R

A06

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1

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

217R

A03

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1

23

The forked opening (2) must face towards the brake band.

: Insert the lever (1) in the side of the bearing boss (arrow).

217R

A03

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2

1

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

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

2

1

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

1 217R

A03

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24

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

Do not grease the brake band.

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

217R

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G

1

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

1

217R

A04

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

Check correct position of the protective tube.

217R

A04

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G

a = 31 mmb = 44 mm

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

217R

A04

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G

1

MS 192 T

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


217R

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1

2

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.

– Check operation of the chain brake, b 7

MS 192 T



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

2

1

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G


217R

A04

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G

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

217R

A04

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G

1

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

217R

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G

1 234

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

217R

A04

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G

1

7.2 Chain Tensioner

25

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

217R

A04

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G

12

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

217R

A05

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G

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

217R

A05

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12

26

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

Always replace the adjusting screw

217R

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and spur gear together.

– Ensure that the parts are installed in the correct order.

– Check correct functioning.

– Coat the threads and gear wheels with STIHL multi-purpose grease,b 16


– Check correct functioning again.


– Fit the stud puller on the collar stud (1).

217R

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G

1

: Push the stud puller (1) 5910 893 0501 over the collar stud as far as possible and unscrew the collar stud anticlockwise.


217R

A05

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G

1

– Fit the collar stud and tighten it down firmly.



7.3 Bar Mounting Stud

MS 192 T

Check and if necessary repair the fuel supply, carburetor, air filter and ignition system before looking for faults on the engine.



Screen


217R

A05

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G

: Remove the cover plate (2) and spark arresting screen (1) if fitted.

– Clean the spark arresting screen (1) or replace if necessary.

12

217R

A05

6 T

G

MS 192 T


217R

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G

– Remove and examine the muffler, replace if necessary.

– Clean the sealing faces.

A gasket is not fitted between muffler and cylinder.

217R

A06

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order.

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.

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.

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

The crankcase can be thoroughly checked for leaks with the

carburetor and crankcase tester and the vacuum pump.

8. Engine8.1 Muffler / Spark Arresting

8.2 Leakage test

27


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

– Fit the spark plug and tighten it down firmly.

: 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.

217R

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1

The sealing plate must fill the full

width between the screws.

– Remove the carburetor, b 14.2

28

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

217R

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1

2

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

1

217R

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G

– Fit the test flange 1128 850 4200 (1).

: Screw on the nuts (arrows) and tighten them down firmly.

217R

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1

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.

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

217R

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G

1

: Close the vent screw (1).

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

217R

A06

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G

1 2

0,2

0,4

0

0,6

0,8

1,0

100

200300400

500

600

700

8.2.1 Preparations
8.2.2 Vacuum test
MS 192 T

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.

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

– Remove the test flange.

– Install the carburetor, b 14.2

– Release the muffler and pull out the sealing plate.

– Tighten down the muffler.



– Continue with pressure testb 8.2.3

MS 192 T

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

: Connect pressure hose (1) of tester 1106 850 2905 to nipple (arrow).

217R

A06

7 T

G

1

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

VA

146R

A06

3

1

: 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.

0

0,2

0,4 0,6

0,8

1,0

217R

A06

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G

– If the pressure drops, the leak

must be located and the faulty part replaced.

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 testb 8.2.2

8.2.3 Pressure test

29

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.

It is not necessary to disassemble the complete engine in order to

2

217R

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G1

replace the oil seals.

Ignition side

– Remove fan housing, b 10.2

– Remove the flywheel, b 9.5

– 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.

217R

A27

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30

– Clamp the puller arms.

– Pull out the oil seal.

Avoid damage to the crankshaft stub.

– 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

– 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).

217R

A29

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1

2

The seating face must be flat and

free from burrs.

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

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


Clutch side



– Remove the oil pump, b 13.3

– 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.21

7RA

070

TG

– Pull out the oil seal.


– 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

8.3 Oil Seals

MS 192 T

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

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

1

2

217R

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crankcase.

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

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


MS 192 T

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


– Remove the muffler, b 8.1

217R

A08

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G


– Remove the oil pump, b 13.3


– Remove the ignition module,b 9.1

– Remove the flywheel, b 9.5


217R

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G

1


217R

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G

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

217R

A10

7 T

G

1

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

1

217R

A10

9 T

G

8.4 Engine8.4.1 Removal

31

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

217R

A07

2 T

G

1

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

217R

A10

4 T

G

1

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

217R

A10

5 T

G

32

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

217R

A10

6 T

G

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

217R

A15

3 T

G

: Pull the engine out of the engine housing.

217R

A11

0 T

G

: Push engine into engine housing.

217R

A15

2 T

G

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

217R

A15

3 T

G

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

217R

A10

5 T

G

8.4.2 Installation

MS 192 T

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

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

217R

A10

6 T

G

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

– Fit the guide bar.

217R

A35

7 T

G

MS 192 T

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

217R

A02

1 T

G

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

121

7RA

352

TG

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

– Now tighten down the screws securing the engine.

217R

A35

1 T

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1


– Remove the sprocket cover again.

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

: Push the manifold (1) onto the intake stub.

– Coat the manifold with STIHL Press Fluid, b 16

217R

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1

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

: Press in the supporting plate (1).

217R

A27

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1

33

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

217R

A27

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: Insert and tighten down the screw (1).


217R

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1

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

217R

A15

7 T

G

1

34

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


217R

A15

8 T

G

1


217R

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

217R

A11

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G

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

217R

A11

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8.5 Crankshaft8.5.1 Removal

MS 192 T

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

217R

A11

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G

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

217R

A11

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MS 192 T

– 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

217R

A14

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1

2

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.

– Check that the piston rings have been installed correctly.

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

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

217R

A14

3 T

G

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

217R

A14

4 T

G

1

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 –

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

: Remove the clamping strap.

217R

A14

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G

8.5.2 Installation

35

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

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

217R

A14

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G

Whenever the engine pan has been

disassembled, the mating faces must be cleaned and fresh sealing compound applied, b 16

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

217R

A11

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1

36

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.

2

217R

A08

5 T

G1

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

217R

A14

9 T

G

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

217R

A15

0 T

G

: 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).

217R

A15

1 T

G

– 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.

217R

A14

7 T

G: Apply sealing compound to the

groove on the circumference (arrows)b 16

MS 192 T

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

217R

A14

8 T

G

1

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

: Tighten the screws (arrows) down crosswise.

217R

A11

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G



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

– Install the engine, b 8.4.2


MS 192 T

– Remove the engine, b 8.4.1

– Remove the crankshaft, b 8.5.1

: Remove the ball bearing (1) and washer.

1

217R

A11

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G

: Remove the ball bearing (1) and washer.

376R

A12

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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

376R

A12

8 T

G

13 2

oil seals must always be replaced

when installing a new crankshaft.

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

: Fit the washer (1).

376R

A13

3 T

G

1

8.5.3 Crankshaft / Bearing

37

: 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).

376R

A12

2 T

G

– Slip the deep groove ball bearing

onto the crankshaft stub as far as the washer.

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.

376R

A12

3 T

G

1

38

: Fit the washer (1).

376R

A13

2 T

G

1

: 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).

376R

A12

0 T

G

– Slip the deep groove ball bearing

onto the crankshaft stub as far as the washer.

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.

– Coat the needle bearing with oil.

– Install the piston, b 8.6.2

1

217R

A11

9 T

G

– Install the crankshaft and oil seals,b 8.5.2


MS 192 T

Remove the engine, b 8.4.1

Remove the crankshaft, b 8.5.1

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

217R

A12

4 T

G

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

217R

A12

5 T

G

1

MS 192 T

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

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

217R

A12

6 T

G

12

during this process to ensure that

jolts are not transmitted to the connecting rod.

: Remove the piston (1) from the connecting rod.

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

1

217R

A12

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G

– 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

1

217R

A13

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G

end.

: 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.

217R

A13

5 T

G

1

8.6 Piston8.6.1 Removal

8.6.2 Installation

39

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

217R

A13

6 T

G

12

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

217R

A13

7 T

G

1

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

2 1 376R

A11

1 T

G

40

: 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.

2 1

217R

A13

8 T

G

: 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).

217R

A13

9 T

G

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

The inner pin must point towards the flat face.

376R

A32

7 T

G

: Apply assembly tool5910 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.

The tool must be precisely aligned

217R

A14

0 T

G

in axial direction of the piston pin.

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

217R

A14

1 T

G

1

2

MS 192 T

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

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

– Install the crankshaft, b 8.5.2

217R

A11

7 T

G21

7RA

117

TG


MS 192 T

– Remove piston, b 8.4.1

– Remove piston rings from piston.

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

217R

A12

9 T

G

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

217R

A13

0 T

G

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

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

217R

A13

1 T

G

– Install the piston, b 8.4.2

8.7 Piston rings

41

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.

Troubleshooting on the ignition system should always start with the spark plug, b 4.5

– Remove the fan cover, b 9.1.1

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

2 1

217R

A09

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G

42

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

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

1 2

217R

A32

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G

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

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

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.

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

217R

A08

7 T

G

1

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

217R

A00

8 T

G

1

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

1 217R

A00

9 T

G

9. Ignition System
9.1 Ignition Module 9.1.1 Removing and installing
MS 192 T

: Disconnect the short circuit line (1).


: Disconnect the ground wire (2).

217R

A09

9 T

G

1

2


217R

A10

0 T

G

: Remove the cable guide (arrow).

217R

A10

1 T

G

MS 192 T

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

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

217R

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1 2

A damaged ignition lead can only be

replaced together with the ignition module.

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


– Moderately tighten the screws on the ignition module.

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

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: 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.

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1

– Tighten down the screws.



43

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.

44

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

Using the ZAT 4 ignition system tester 5910 850 4503

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


VA

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321

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

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.

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 (2), check the ignition system with the aid of the troubleshooting chart, b 9.7

Using the ZAT 3 ignition system tester 5910 850 4520

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


6RA

134

TG

1

2 3 4

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

: Attach ground terminal (1) to the spark plug.

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

9.2 Ignition Timing
9.3 Testing the Ignition Module
MS 192 T

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).

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1

3 4

5

2

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.

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

MS 192 T

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

– Remove the ignition module, b 9.1.1

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

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1

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

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1

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

– Unhook the torsion spring from the ignition lead.

– Pull the boot off the ignition lead.

VA

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– 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.

1 2 3

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9.4 Ignition Lead / Spark Plug Boot

45

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

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

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– 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.

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46

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

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

Do not use either graphite grease or silicone insulating paste.

– Install the ignition module, b 9.1

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1

– Reassemble remaining parts in

reverse order.

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

– Block the piston with the locking strip, b 6

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1

: Remove the flywheel nut (arrow).

– Remove the flywheel.

Use the puller if the flywheel is stuck.

1

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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.

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9.5 Flywheel

MS 192 T

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

: Remove the flywheel (1).

1

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

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MS 192 T

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


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

– Set the air gap between ignition coil and flywheel, b 9.1.1


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reverse order.


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


1

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

– Set the switch shaft to "0".

The resistance measured must be about 0 �. 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


9.6 Short Circuit Wire9.6.1 Testing

47


– Remove the handle moulding and actuating levers, b 12.1

– Remove the switch shaft, b 12.3


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1

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


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1

2

48

: Remove the cable guide (arrow).

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: Remove the cable guides (arrows).

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

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: 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.

321

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– Plug the contact spring (1) into the terminal socket of the wiring harness.

: Place the contact springs in the guides (arrows).

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1

9.6.2 Removing and installing

MS 192 T

: 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

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1

2

3

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".


– Set the air gap between ignition coil and flywheelb 9.1.1



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

necessaryb 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

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

b 9.5

Air gap: – Check ignition module / flywheel,

– Adjust if necessary, b 9.1.1

Check ignition lead: – Severe chafing?

– Spark plug boot: holes / cracks?– Resistance of spark plug boot to ground:

required: 1.5...12 k��– Check resistance of ignition lead:

value required < 10 ��– Replace spark plug boot and/or ignition lead

with ignition module if necessaryb 9.4

Check short circuit wire:

– Replace short circuit wire if necessaryb 9.6.1

1

3

yes

no

Spark present?

2

51MS 192 T

Engine runs smoothly,troubleshooting procedure completed

no

Replace ignition module

b 9.1.1

yes

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

yes

Stop switchCheck 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 necessaryb 9.6.2

2 3

Spark present?

Engine runs

52 MS 192 T

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.

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.

– Clean all components.

MS 192 T


– Remove the fan housing (1).

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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.

1

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

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1


– Tighten down the screws.


10. Rewind starter10.1 General

10.2 Removing and Installing

53


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

1

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: Remove the pawl (1).

– Grease the pegs (arrow) of the new pawl, b 16


1

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54


– Remove the spring, b 10.3

Relieve tension of rewind spring

: 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.

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– 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.

: Remove the washer (1).

: Remove the pawl (2).

The rewind spring must be relieved.

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2

: 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,

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– 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

10.3 Pawls
10.4 Rope Rotor
MS 192 T

: 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.

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1


reverse order.

MS 192 T

: 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.

1

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– Then slide the straight part of the

spring over the starter post until it engages in the groove.

– Tension the rewind spring, b 10.6

– Grease the pegs of the pawls, b 16

– Remove the fan housing, b 10.2

– 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.

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

VA

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10.5 Starter Rope / Grip

55

Machines with standard starter grip

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

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TG

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

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

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56

Machines with ElastoStart starter grip

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

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1

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

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1

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

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

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

– Press the cap into the starter grip.

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1

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

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

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1

MS 192 T

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

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

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– Install the rope rotor and tension

the rewind spring, b 10.4

– Install the fan housing, b 10.2


MS 192 T


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

: Turn the rope rotor with rope six

1

2

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times clockwise.

The rope twists as the rope rotor and rope are turned. The rewind spring is now tensioned.

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

– Hold the rope rotor (2) steady.

: Pull out the rope (1) with the starter grip and straighten it out.

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21

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

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

1

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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.

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1

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 –

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

– Install the fan housing, b 10.2


10.6 Tensioning the Rewind Spring

57


The replacement spring is supplied ready for installation and secured in a frame.

Wear a face shield and protective gloves.


– Relieve the rewind spring if necessary and remove the rope rotor, b 10.4

– Remove any fragments of the old spring.

– Lubricate the spring with a few drops of STIHL special lubricant

before installation, b 16

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

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58

: 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.

– Remove the frame.

The rewind spring may pop out.

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

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

1

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– Arrange the spring (1) as shown in the illustration.

: Position the anchor loop in the fixture (arrow).

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

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

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10.7 Replacing the Rewind Spring

MS 192 T

: 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


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MS 192 T

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.


– Relax the rewind spring and remove the starter rope and rope rotor, b 10.4

– 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.

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1

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

1

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: 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

1

2

3

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end of the rope bushing.

– Remove the installing tool.


10.8 Starter Rope Guide Bushing

59

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.

60

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

Remove the sprocket cover and bar and chain, b 5.1


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– Remove the rubber buffer.

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: Examine the rubber buffer and replace it if necessary.



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11. Repairing the AV System
11.1 Annular Buffer
MS 192 T

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

– Open the handle housing, b 12.1

– Remove the throttle trigger and throttle trigger interlock, b 12.1

– Remove the switch shaft, b 12.3


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

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MS 192 T

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

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1

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

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

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21

3

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


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1

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

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: Insert and tighten down the screw (arrow).



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11.2 Front Handle / Spring

61

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.


– Open the handle housing, b 12.1

Housing


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

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1

62


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

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– Examine the AV spring and replace it if necessary,

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

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order.


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

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

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

– Examine the clamp and replace it if necessary,

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: Press the clamp (1) into the engine housing from below.


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1

11.3 AV Spring between Handle Housing / Engine

11.4 Clamp

MS 192 T


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– 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.

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– Insert and tighten down the

screw.


MS 19

STIHL MS 192 T€¦ · STIHL parts symbol (The symbol may appear alone on small parts. 1....

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Transcript of STIHL MS 192 T€¦ · STIHL parts symbol (The symbol may appear alone on small parts. 1....