STIH)
Contents
1. Introduction 2
2. Safety Precautions 3
3. Specifications 4
3.1 Engine 4
3.1.1 Engine (USA only) 4
3.2 Fuel System 5 3.3 Ignition System 5 3.4 Chain Lubrication 5 3.5 Tightening Torques 6 4. Troubleshooting Chart 8
4.1 Clutch, Chain Drive,
Chain Brake, Chain Tensioner 8 4.2 Rewind Starter 9 4.3 Chain Lubrication 10 4.4 Ignition System 11 4.5 Carburetor 12 4.6 Engine 14
5. Clutch, Chain Drive,
Chain Brake and
Chain Tensioner 15
5.1 Clutch Drum / Chain
Sprocket 15 5.2 Chain Catcher 16 5.3 Clutch 16 5.4 Chain Brake 18 5.4.1 Checking Operation 18 5.4.2 Removing 19 5.4.3 Installing 20
5.5 Front Chain Tensioner 22
5.6 Side Chain Tensioner 22
6. Engine 23 6.1 Muffler/Spark Arresting Screen 23 6.2 Leakage Test 24 6.2.1 Preparations 24 6.2.2 Pressure Test 25 6.2.3 Vacuum Test 26 6.3 Oil Seals 26 6.4 Removing and Installing 28 6.5 Cylinder 29 6.6 Piston 31 6.7 Piston Rings 33 6.8 Crankshaft 33 6.9 Decompression Valve 34 7. Ignition System 34
7.1 Spark Plug Boot 35
7.2 Ignition Module 35 7.3 Testing the Ignition Coil 36 7.4 Checking the Wiring Harness 36 7.4.1 Ignition Timing 37 7.4.2 Removing and Installing 37 7.5 Flywheel 38 7.6 Ignition System Troubleshooting 39 8. Rewind Starter 42 8.1 General 42 8.2 Removing and Installing 42 8.3 Rope Rotor 42 8.4 Segment 44 8.5 Starter Rope 44 8.5.1 Elastostart 45 8.5.2 Tensioning 46 8.6 Rewind Spring 47 8.7 Pawl 48 9. AV Handle System/ Handle Housing 48 9.1 Annular Buffers 48 9.2 Front Handle 49 9.3 Handle Housing 50 9.4 Switch Shaft 52 9.5 Contact Spring 52 9.6 Throttle Trigger/ 10. Chain Lubrication 54 10.1 Pickup Body 54 10.2 Connector/ Suction Hose 55 10.3 Valve 55 10.4 Worm 56 10.5 Oil Pump 57 11. Fuel System 58 11.1 Air Filter 58 11.2 Carburetor 59 11.2.1 Leakage Test 59 11.2.2 Removing and Installing 60 11.2.3 Adjusting (Carburetor
without Limiter Cap) 61 11.2.4 Adjusting (Carburetor with Limiter Cap) 62 11.2.5 Standard Setting (Carburetor with Limiter Cap) 62 11.3 Tank Vent 63 11.4 Pickup Body 64 11.5 Suction Hose 64
11.6 Manual Fuel Pump 65
11.7 Hoses 65
11.8 Fuel Tank 67
12. Special Servicing
Tools 69
This service manual contains detailed descriptions of all the repair and servicing procedures specific to this power tool series.
As the design concept of model MS 210, 230 and 250 chainsaws is almost identical, the descriptions and servicing procedures in thus manual generally apply to all three models. Differences are described in detail.
You should make use of the illustrated parts lists while carrying out repair work. They show the installed positions of the individual components and assemblies. Refer to the latest edition of the relevant parts list to check the part numbers of any replacement parts. A fault on the machine may have several causes. To help locate the fault, consult the troubleshooting charts for all assemblies and systems in this manual and the "STIHL Service Training System". 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 until a revised edition is issued.
The special tools mentioned in the descriptions are listed in chapter "Special Servicing Tools" of this manual. Use the part numbers to identify the tools in the "STIHL Special Tools" manual. The manual lists all 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 descriptions:
: = Action to be taken as shown in the illustration (above the text)
– = Action to be taken that is not shown in the illustration (above the text)
In the illustrations: A Pointer (short)
aDirection of movement (long) b 4.2 = Reference to another
chapter, i.e. chapter 4.2 in this example.
Service manuals and all technical Information bulletins are intended exclusively for the use of STIHL servicing dealers. They must not be passed to third parties.
Servicing and repairs are made considerably easier if the clamp (1) 5910 890 2000 is used to mount the machine on assembly stand (2) 5910 890 3100 so that one clamp screw engages the outer 10 mm bore (3) in the assembly stand. To service the underside of the machine (e.g. remove the oil pump), turn the machine through
180 degrees and mount it so that one clamp screw engages the inner 10 mm bore (1) in the assembly stand.
Note:
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,
the STIH) logo
and the STIHL parts symbol ( This symbol may appear alone on small parts.
If the engine is started up in the course of repairs or maintenance work, observe all local and country-specific safety regulations as well as the safety precautions and warnings in the owner’s manual. Gasoline is an extremely flammable fuel and can be explosive in certain conditions.
Improper handling may result in burns or other serious injuries. Warning!
Do not smoke or bring any fire, flame or other source of heat near the fuel. All work with fuel must be performed outdoors only. Spilled fuel must be wiped away immediately.
3. Specifications 3.1 Engine MS 210 MS 230 MS 250 Displacement: 35.2 cm3 40.2 cm3 45.4 cm3 Bore: 40 mm 40 mm 42.5 mm Stroke: 28 mm 32 mm 32 mm
Engine power to ISO 7293: 1.6 kW (2.2 HP)
at 9,000 rpm 2.0 kW (2.7 HP)at 10,000 rpm 2.3 kW (3.1 HP)at 10,000 rpm
Max. permissible engine speed
(with bar and chain): 12,500 rpm 14,000 rpm 14,000 rpm
Idle speed: 2,800 rpm
Clutch: Centrifugal clutch without linings
Clutch engages at: 4,100 rpm
Crankcase leakage test
at gauge pressure: 0.5 bar
under vacuum: 0.5 bar
3.1.1 Engine (USA only)
MS 210 MS 230 MS 250
Displacement: 2.15 cu. in 2.45 cu. in 2.77 cu. in
Bore: 1.57 in 1.57 in 1.67 in
Stroke: 1.10 in 1.26 in 1.26 in
Engine power to ISO 7293: 1.5 kW (2.01 HP) 1.9 kW (2.55 HP) 2.2 kW (2.95 HP)
Max. permissible engine speed
(with bar and chain): 12,500 rpm 14,000 rpm 14,000 rpm
Idle speed: 2,800 rpm
Clutch: Centrifugal clutch without linings
Clutch engages at: 4,100 rpm
Crankcase leakage test
at gauge pressure: 7.25 psi
3.2 Fuel System Carburetor leakage test
at gauge pressure: 0.8 bar (11.6 psi)
Function of tank vent
at gauge pressure: 0.3 bar (4.35 psi)
0.05 bar (0.72 psi)
Fuel: see owner’s manual
3.3 Ignition System
Air gap between ignition module
and fanwheel: 0.2 – 0.4 mm (0.008 – 0.015 in)
Spark plug (resistor type): Bosch WSR 6F
NGK BPMR 7A
Electrode gap: 0.5 mm (0.02 in)
3.4 Chain Lubrication
Fully automatic speed-controlled oil pump with rotary piston
3.5 Tightening Torques
DG screws are used in the polymer and light-alloy components. These screws form a permanent thread when they are installed for the first time. They can be removed and installed as often as necessary without
detrimentally affecting the strength of the screwed assembly, providing the specified tightening torque is observed. For this reason always use a torque wrench.
Fastener Thread
size For component Torque Remarks
kpm Nm
Spline screw IS-M4x15 Cain brake cover 0.2 2.0
Spline screw IS-D4x15 Handle molding 0.16 1.6
Spline screw IS-P5x16 Connector (engine housing/oil pump) 0.4 4.0
Spline screw IS-M4x15 Ground wire (to cylinder) 0.35 3.5
Spline screw IS-DG5x24 Handle housing/front handle 0.35 3.5
Spline screw IS-DG5x24 Hand guard 0.35 3.5
Spline screw IS-DG5x24 Fan housing 0.35 3.5
Spline screw IS-DG5x24 Buffer (to front handle) 0.35 3.5
Spline screw IS-DG5x24 Buffer (to engine housing) 0.35 3.5
Spline screw IS-DG5x24 Ignition module (to engine housing) 0.4 4
Spline screw IS-DG5x24 Cylinder (to engine housing) 0.95 9.5
Collar screw DG 8x18 Guide bar mounting 1.6 16
M12x1 Carrier (clutch) 5.0 50
M14x1.25 Spark plug 2.5 25
Collar locknut M5 Muffler 0.8 8
Collar locknut M5 Filter housing/carburetor 0.27 2.7
Collar nut M8x1 Flywheel to crankshaft 2.8 28
M12x1.5 Decompression valve 1.4 14
Use the following procedure to fit a DG screw in an existing thread:
– Place the DG screw in the hole and rotate it counterclockwise until 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, which would weaken the assembly.
Note:
Power screwdriver speed setting for polymer:
4. Troubleshooting Chart
4.1 Clutch, Chain Drive, Chain Brake, Chain Tensioner
Condition 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
Brake band stuck Check freedom of movement and
function of brake band
Saw chain rotates at idle speed Engine idle speed too high Readjust with idle speed screw
(counterclockwise)
Clutch springs stretched or fatigued Replace the clutch springs
Clutch spring hooks broken Replace the 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
Chain sprocket wears rapidly Chain not properly tensioned Tension chain as specified
Wrong chain pitch Fit chain of correct pitch
Saw chain does not stop immediately when brake is activated
Brake spring stretched or broken Fit new brake spring
Brake band stretched / worn /
4.2 Rewind Starter
Condition 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
(rope does not rewind) Spring overtensioned – no reserve when rope is fully extended Fit new rewind spring
Very dirty or corroded Clean or replace rewind spring
Starter rope can be pulled out almost without resistance (crankshaft does not turn)
Guide peg on pawl or pawl itself is worn
Fit new pawl
Spring clip fatigued Fit new spring clip
Starter rope is difficult to pull
and rewinds very slowly Starter mechanism is very dirty (dusty conditions) Thoroughly clean complete starter mechanism
Lubricating oil on rewind spring becomes viscous at very low outside temperatures (spring windings stick together)
Apply a few drops of kerosine (paraffin) to spring, then pull rope carefully several times until normal action is restored
4.3 Chain Lubrication Important!
In the event of trouble with the chain lubrication system, always
investigate the other possible sources of faults before disassembling the oil pump.
Condition 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
Intake hose or pickup body (strainer) clogged or intake hose ruptured
Wash intake hose and pickup body (strainer) in fresh STIHL cleaner or replace if necessary
Valve in oil tank blocked Clean or replace valve
Oil pump damaged or worn Install new oil pump
Machine losing chain oil Oil seal leaking Replace oil seal
Bore in pump housing worn Install new oil pump
4.4 Ignition System Warning!
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!
Condition 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
Weak spark or no spark Faulty insulation on ignition lead or
short circuit wire. Use ohmmeter to check ignition lead for break. If break is detected or high resistance measured, fit a new ignition lead Incorrect air gap between ignition
coil and flywheel Set air gap correctly
Flywheel cracked or has other damage
Install new flywheel
Crankcase damaged (cracks) Install new crankcase
No ignition spark Check operation of Master Control
lever, ignition module and ignition lead
4.5 Carburetor
Condition Cause Remedy
Carburetor floods;
engine stalls Inlet needle not sealing. Foreign matter in valve seat or cone
damaged
Remove and clean or replace the inlet needle, clean the fuel tank, pickup body and fuel line if necessary
Inlet control lever sticking on spindle
Free off 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
Inlet control lever too high (relative to design position)
Set inlet control lever flush with top edge of housing or bottom of metering chamber
Poor acceleration Idle jet too lean Back off low speed screw (L)
slightly
Main jet too lean Back off high speed screw (H)
slightly Inlet control lever too low
(relative to design position)
Set inlet control lever flush with top edge of housing or metering chamber face
Inlet needle sticking to valve seat Remove inlet needle, clean and
refit Connecting bore to atmosphere
blocked Clean bore
Diaphragm gasket leaking Fit a new diaphragm gasket
Metering diaphragm damaged or
Condition 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
Engine leaking Seal the engine
Engine stalls at idle speed Idle jet bores or ports blocked Clean jet bores and ports with
compressed air
Idle jet too rich Screw down low speed screw (L)
slightly Setting of idle speed (LA)
incorrect – throttle shutter completely closed
Set idle speed screw (LA) correctly
Small plastic plate in valve jet
does not close Clean or renew valve jet
Engine speed drops quickly under
load – low power Air filter plugged Clean or renew the air filter
Tank vent faulty Clean tank vent or replace if
necessary Leak in fuel line between tank and
fuel pump Seal connections or install new fuel line
Pump diaphragm damaged or
fatigued Fit a new pump diaphragm
Main jet bores or ports blocked Clean the bores and ports
Fuel pickup body dirty Clean the pickup body, fit a new
filter
4.6 Engine
Always check and, if necessary, repair the following parts before looking for faults on the engine: – Air filter
– Fuel system – Carburetor – Ignition system
Condition Cause Remedy
Engine does not start easily, stalls at idle speed, but operates normally at full throttle
Oil seals in crankcase damaged Replace the oil seals
Gasket on carburetor spacer flange
leaking Fit a new gasket
Engine pan leaking Seal the engine pan
Crankcase damaged (cracks) Replace the crankcase
Muffler leaking Seal or replace the muffler
Engine does not deliver full power or runs erratically
Secondary air seepage through leaking gaskets on carburetor spacer flange
Fit new gaskets
Piston rings worn or broken Fit new piston rings
Muffler / spark arresting screen
carbonized Clean the muffler (inlet and exhaust), replace spark arresting
screen
Air filter element dirty Replace air filter element
Fuel / impulse line severely kinked or damaged
Replace lines or position them free from kinks
Decompression valve sticking Replace the decompression valve
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
– Remove the chain sprocket cover.
: Disengage the chain brake by pulling the hand guard toward the front handle.
VA
143RA004
: Remove the E-clip (1). : Remove the washer (2).
– Remove the rim sprocket, if fitted. : Pull off the clutch drum / chain
sprocket.
: Take the needle cage out of the sprocket.
– Clean and inspect the clutch drum / chain sprocket.
VA
143RA007
: Inspect the clutch drum (1) for signs of wear.
If there are noticeable wear marks on the inside diameter of the clutch drum, check its wall thickness. If it is less than 80% of the original wall thickness, fit a new clutch drum.
VA 148RA101 80% 100%
1
!
If the clutch drum has to be
replaced, also check the brake band – b 5.4.
: If the clutch drum/chain sprocket is still serviceable, use No. 120 emery paper or emery cloth (grain size approx. 120 µm) to clean and roughen its friction surface.
Reassemble in the reverse
VA
176RA330
sequence.
– Clean stub of crankshaft. Wash needle cage in clean white spirit and lubricate with grease – b 13.
– Replace damaged needle cage. – Rotate clutch drum/chain
sprocket and apply slight pressure at the same time until oil pump drive spring engages properly.
– If rim sprocket was fitted, re-install it with the cavities facing outward.
5. Clutch, Chain Drive,
Chain Brake and Chain Tensioner
5.1 Clutch Drum / Chain
: Sprocket cover with integrally molded chain catcher.
If the chain catcher has broken off, repair as follows:
VA
208RA001
: Remove the chain bumper strip (1).
: Pry the plug (2) out of the front right-hand AV element. VA 2 08RA000
2
1
: Oil the cylindrical part (1) of the replacement chain catcher. : Push the chain catcher into the
AV element (2) and engage the peg (3) in the housing bore (4) at the same time.
VA 208RA003
1
4
3
2
– Fit the chain bumper strip. Assemble all other parts in the reverse sequence.
Troubleshooting chart – b 4.1. – Remove the clutch drum/chain
sprocket – b 5.1.
– Remove the air filter – b 11.1.
: Take out the shutter. – Pull boot off the spark plug. – Unscrew the spark plug.
– Close the decompression valve, if fitted.
: Push the locking strip (1) 0000 893 5903 into the cylinder.
VA
135RA022
1
: Unscrew the clutch from the crankshaft clockwise (left-hand thread).
VA
135RA023
Disassembling the clutch: : Use hook (2) 5910 890 2800 to
remove the clutch springs (1). – Pull the clutch shoes off the
carrier.
VA
208RA028
2
1
: Pull the retainers, if fitted, off the clutch shoes.
VA
208RA031
– Clean all parts with STIHL cleaner.
– Replace any damaged parts.
VA
208RA026
Assembling the clutch:
: Slip the retainers onto the clutch shoes.
VA
208RA029
: On retainers with tabs (1), the narrow side (2) must be next to the series number (3).
VA
208RA032
3
1 2
: Fit the clutch shoes over the arms (1) of the clutch carrier so that the series number (2) is on the same side as the larger hexagon (3).
VA
208RA027
2
1
3
: Clamp the clutch in a vise.
VA
: Attach one end of each spring (1) to the clutch shoes.
: Use the hook (2) 5910 890 2800 to attach other ends of springs and press them firmly into the clutch shoes.
VA
208RA033
1
2
: Screw on the clutch and tighten down to 50 Nm (37 lbf.ft). – Install the clutch drum / chain
sprocket – b 5.1.
VA
135RA024
– Remove locking strip from the cylinder.
– Insert spark plug and tighten down to 25 Nm (18.5 lb.ft). : If spark plug has a separate
terminal nut, make sure it is
VA
250RA008
properly tightened down. – Fit boot on the spark plug.
: Fit the shutter so that its lugs engage the recesses in the handle housing.
– Install the air filter – b 11.1.
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. Contamination (with chain oil, chips, fine particles of abrasion, etc.) and smoothing of the friction surfaces of the brake band and clutch drum impair the coefficient of friction. 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 throttle wide for a brief period (max. 3 seconds) – the chain must not rotate. – With the chain brake released,
open 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.
5.4 Chain Brake
– Remove the clutch drum / chain sprocket – b 5.1.
– Release brake spring tension by pushing hand guard forward. – Remove upper bumper strip from
the tensioner.
: Take out the screws. – Remove the cover.
VA
135RA026
: Carefully ease the brake spring off the anchor pin and take it off the bell crank.
: Pry the brake band out of the engine housing.
– Disconnect the brake band from the bell crank.
VA
135RA027
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 (0.024").
VA
170RA014
Important!
Thickness of brake band must not be less at any point.
: If the brake band is still
serviceable, use No. 120 emery paper or emery cloth (grain size approx. 120 µm) to clean and roughen its entire friction surface (inside diameter).
: Remove the screw (arrow) from the hand guard.
VA
135RA028
: Remove the E-clip.
VA
135RA029
: Remove strap from bell crank pivot pin (1).
: Push the strap sideways and lift it off the hand guard pivot pin (2).
VA
135RA030
2 1
: Remove the washer.
VA
135RA031
: Carefully pry the hand guard (1) and bell crank (2) off their pivot pins and lift away together. – Pull the bell crank out of the hand
guard.
135RA032
1
2 VA
: Remove the flat spring. – Inspect parts and replace if
damaged.
– Clean the entire housing recess for the chain brake.
– If the groove of the brake spring anchor pin is worn, replace the housing.
– Lubricate sliding and bearing points of chain brake with STIHL multipurpose grease or,
preferably, molybdenum grease (e.g. Molykote) – b 13.
– Install the flat spring.
: Insert the bell crank in the side of the hand guard so that the short arm of the bell crank points to top of hand guard.
VA
135RA034
: Position the hand guard (1) against the pivot pin and fit the other side of the hand guard over the housing.
: Position the bell crank (2) against the pivot pin.
VA
208RA109
2
1
: Push the hand guard and bell crank onto their pivot pins.
: Check that flat spring (1) is properly located on face (2) of hand guard bearing boss.
VA
135RA036
1 2
: Fit the washer.
VA
135RA031
: Fit strap on the pivot pin (1) and engage it in the pivot pin's groove.
: Slip the other end of the strap over the bell crank pivot pin (2). – Secure strap with E-clip.
VA
135RA037
1 2
– Coat the brake band with chain oil (STIHL Bioplus), b 13, to protect it from corrosion and help reduce "snatching" during the first few brake applications.
: Hook the brake spring onto the bell crank.
VA
135RA038
: Position the brake band around the clutch and push it into the engine housing.
VA
135RA039
: Attach the brake spring to the bell crank. V A 13 5R A 04 0
: Use the hook (2) 1117 890 0900 to attach the brake spring (1) to the anchor pin.
VA
135RA041
1
2
– Fit the bushing (1) in the hand guard (2).
: Insert M5x24 screw (3) and tighten down to 3.5 Nm (2.6 lbf.ft).
– Fit the cover.
VA 208RA004
3
1
2
– Tighten screws to 2.0 Nm (1.5 lbf.ft).– Fit upper bumper strip on tensioner.
– Install clutch drum/chain sprocket – b 5.1.
– Check operation of chain brake – b 5.4.1.
– Remove the chain sprocket cover.
: Pull the cover out of the housing.
VA
135RA043
: Unscrew the nut (1) from the adjusting screw (2).
: Take the adjusting screw out of the cover (3).
Reverse the above sequence to install the chain tensioner.
143RA052
VA
1
2
3
– Remove the chain sprocket cover.
: Take out the screw.
– Pull tensioner assembly out of the engine housing.
VA
135RA044
: Take the thrust pad (1) off the adjusting screw (2).
: Rotate the spur gear (3) until the adjusting screw comes out of the tensioner slide (4).
VA
135RA045
1 4 2 3
: Pull the spur gear out of the cover.
VA
135RA046
: Pull the tensioner slide off the cover.
– Take the adjusting screw out of the cover.
– Inspect the teeth on the spur gear and adjusting screw. Replace
VA
135RA047
both parts if necessary. Reverse the above sequence to install the chain tensioner.
– Coat teeth of adjusting screw and spur gear with grease, b 13, before refitting.
This machine does not have a conventional crankcase. The engine consists of the cylinder, piston, crankshaft and engine pan. Troubleshooting chart – b 4.6.
: Unscrew the nuts. – Remove the muffler.
VA
135RA048
: Pull off or lever off the cover plate – depending on type fitted. – Remove spark arresting screen,
if fitted. Clean the screen or fit a
VA
208RA006
: Muffler with push-fit upper and lower casings: Remove the upper casing from the lower casing.
VA
135RA051
: Muffler with push-fit upper and lower casings:
If necessary, take the baffle out of the lower casing.
VA
135RA052
: Remove the gasket (1) and heat shield (2), if fitted. VA 135RA053 2 1 6. Engine 6.1 Muffler/Spark Arresting Screen
: Remove the screws from the flange.
Reassemble in the reverse sequence.
– Use a new gasket.
VA
135RA054
– Fit new locknuts and torque down to 8.0 Nm (5.9 lbf.ft).
Defective oil seals and gaskets or cracks in castings 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.
The engine housing can be checked thoroughly for leaks with the carburetor and crankcase tester and the vacuum pump.
– Remove the muffler – b 6.1. : Fit the sealing plate (1)
0000 855 8106 between the mounting screws.
The sealing plate must completely fill the space between the two mounting screws.
: Slip the flange (2) 1123 855 4200 over the screws.
: Fit the sleeves (3) 1123 851 8300 on the screws.
: Fit the nuts (4) and tighten down securely.
– Remove the carburetor – b 11.2.2.
– Set the piston to top dead center (T.D.C.). This can be checked through the inlet port.
: Inspect carburetor gasket and fit a new one if necessary.
VA
135RA056
: Fit the test flange (1)
1118 850 4200 in place of the carburetor.
: If decompression valve is fitted, pull out the button.
– Check that spark plug is properly tightened down.
– Perform leakage test with tester 1106 850 2905 and vacuum pump 0000 850 3501.
– Carry out preparations – b 6.2.1.
: Connect pressure hose of tester 1106 850 2905 to nipple on test flange.
: Close the vent screw (1) on the rubber bulb.
– Pump air into the engine housing with the rubber bulb until the gauge indicates a pressure of 0.5 bar (7.25 psi). If this pressure remains constant for at least
VA
143RA046
1
20 seconds, the engine or decompression valve, if fitted, is airtight.
: However, if the indicated
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 engine again. Bubbles will appear if
VA
208RA007
a leak exists.
– If the decompression valve is leaking, fit a new one – b 6.9. – Repeat the pressure test. – Carry out the vacuum test –
b 6.2.3.
– After finishing the test, open the vent screw and disconnect the hose.
– Remove the test flange. – Install the carburetor –
b 11.2.2.
– Remove the flange. – Remove the sealing plate. – Install the muffler – b 6.1.
Oil seals tend to fail when subjected to a vacuum, i.e. 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.
– Carry out the preparations – b 6.2.1.
: Connect suction hose of vacuum pump 0000 850 3501 to test flange nipple.
: Close the vent screw (1) on the pump.
: Operate the lever (2) until pressure gauge (3) indicates a
VA
135RA061
2
1 3
If the vacuum reading remains constant, or rises to no more than 0.3 bar (4.25 psi) within 20 seconds, it can be assumed that the oil seals are in good condition.
However, if the pressure continues to rise (reduced vacuum in the engine housing), 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 11.2.2.
– Remove the flange. – Remove the sealing plate. – Install the muffler – b 6.1.
It is not necessary to disassemble the complete engine housing if only the oil seals have to be replaced.
Clutch side:
– Remove the clutch – b 5.3. – Remove the oil pump – b 10.5.
: Ease the retaining ring out of the crankshaft.
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: Apply puller (1) 5910 890 4400 (jaws 0000 893 3711 with No. 6 profile).
– Clamp the puller arms. – Pull out the oil seal.
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1
Take care not to damage the crankshaft stub.
: If an oil seal with clamping ring (1) is installed, use puller and No. 3.1 jaws to remove the clamping ring. Pry the sealing ring (2) out of the housing. – Clean sealing face with STIHL
cleaner – b 13.
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2 1
If the cylinder and engine pan are assembled, only oil seal
9638 003 1581 (with clamping ring) may be installed.
– Lubricate sealing lip of oil seal with grease – b 13.
– Thinly coat the outside diameter of the oil seal with sealant – b 13.
– Place the oil seal in position with the clamping ring faces up. : Use the press sleeve (1)
1123 893 2400 to install the oil seal.
– Wait about one minute, then
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1
rotate the crankshaft. – Fit a new retaining ring. – Install the oil pump – b 10.5. – Install the clutch – b 5.3.
Ignition side:
– Remove the flywheel – b 7.5.
: Apply puller (1) 5910 890 4400 (jaws 0000 893 3711 with No. 6 profile).
– Clamp the puller arms. 1
135RA065
V
Take care not to damage the crankshaft stub.
– Remove oil seal with clamping ring as described for clutch side. – Cleaning sealing face with STIHL
cleaner – b 13.
If the cylinder and engine pan are assembled, only oil seal
9638 003 1581 (with clamping ring) may be installed.
– Lubricate sealing lip of oil seal with grease – b 13.
– Thinly coat the outside diameter of the oil seal with sealant – b 13.
: Place the oil seal (1) in position with the clamping ring facing up. : Screw the guide sleeve (2)
1123 894 7700 onto the 2 1 135RA066 V A
: Use the press sleeve (1) 1123 893 2400 to install the oil seal.
– Wait about one minute, then rotate the crankshaft.
– Install the flywheel – b 7.5.
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1
Always check and, if necessary, repair the fuel system, carburetor, air filter and ignition system before looking for faults on the engine. – Remove the handle housing –
b 9.3.
– Remove the oil pump – b 10.5.
: Pull off the worm with drive spring.
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V
A
: Take out the ground wire fastening screw.
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: Unscrew the engine pan mounting screws.
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: Remove engine sideways from housing.
Install in the reverse sequence. – Tighten down the engine pan
mounting screws to 9.5 Nm (7 lbf.ft) and the ground wire fastening screw to 3.5 Nm (2.6 lbf.ft).
– Remove the engine – b 6.4. – Take out the spark plug. : Remove baffle plate.
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: Pull the manifold (1) off the intake port.
: Disconnect the impulse hose (2). 2
1
135RA073
V
A
: Pull the engine pan off the cylinder.
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: Lift the crankshaft and pull the piston out of the cylinder at the same time.
– Inspect ball bearings and oil seals and replace if necessary – b 6.8.
– Inspect the cylinder and replace it if necessary.
: On easy start version, unscrew the decompression valve. – If a new cylinder has to be
installed, always fit the matching piston. Replacement cylinders are only supplied complete with piston for this reason.
– Thoroughly clean all residue of sealant from the cylinder and engine pan mating faces.
– Apply a thin coating of sealant to the outer diameters of the oil seals – b 13.
– Lubricate piston and piston ring with oil.
: Position the piston rings so that the radii at the ring gap meet at the fixing pin in the piston groove when the rings are compressed.
: Slide piston carefully into the cylinder.
The piston rings are compressed by the inner taper of the cylinder.
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: Position the crankshaft so that the long crankshaft stub (1) points to the right, looking at exhaust port (2).
– Push piston home until ball bearings are seated.
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1
2
: Apply a thin bead of sealant to the engine pan mating face – b 13.
Follow manufacturer’s instructions
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V
A
: Fit the engine pan so that the seat (1) for the oil pump is at the same side as the long crankshaft stub (2).
: On easy start version, unscrew the plug, screw home the decompression valve and tighten it to 14 Nm (10.3 lbf.ft).
: Push the manifold on to the intake port so that the straight faces are in alignment. Assemble all other parts in the
– Pull the piston out of the cylinder – b 6.5.
: Ease the hookless snap rings out of the grooves in the piston bosses.
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: Use the assembly drift (2) 1110 893 4700 to push the piston pin (1) out of the piston.
If the piston pin is stuck, release it by tapping the end of the drift lightly with a hammer. Hold the piston steady during this process to ensure that no jolts are transmitted to the connecting rod.
– Remove the piston from the connecting rod.
– Inspect needle cage and replace if necessary.
If needle cage is press-fitted, replace the crankshaft.
: Inspect piston rings and replace if necessary – b 6.7.
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: Fit needle cage (arrow) in the connecting rod (not MS 210). – Oil the needle cage.
: To ease assembly, heat the piston slightly and push it over the connecting rod.
Installed position of piston:
: Push the assembly drift, small diameter first, through the piston and small end (needle cage) and line up the piston.
: Fit the piston pin (1) on the assembly drift (2) and slide it into the piston (the pin slides home easily if the piston is warm).
: Modify sleeve of the installing tool 5910 890 2210 as shown: a = 16 mm (11/16") b = 8 mm (5/16") VA 135RA093 a b 6.6 Piston
: Remove the sleeve from the tool.
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: Attach the snap ring (1) to the magnet (2) so that the snap ring gap is on the flat side of the tool's shank.
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2
1
: Push the large slotted diameter of the sleeve over the magnet and snap ring. Position the sleeve so that the inner pin (1) points toward the flat face (2) of tool's
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2
1
: Stand the installing tool, sleeve downward, on a flat surface (wooden board) and press vertically downwards until the sleeve butts against the tool's shoulder.
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: Remove the sleeve and slip it onto the other end of the shank. Inner pin must again point toward flat face.
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: Apply the installing tool to the piston boss, hold the piston steady, center the tool shank exactly and press home until the snap ring slips into the groove.
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Fit the snap rings so that their gaps are on the piston's vertical axis (they must point either up or down – see arrow).
– Install the piston – b 6.5.
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– Pull the piston out of the cylinder – b 6.6.
– Remove rings from the piston.
: Use a piece of old piston ring to scrape the grooves clean.
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: Install the new piston rings in the grooves so that the radii face upward.
– Install the piston – b 6.6.
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: The crankshaft (1) and connecting rod are an
inseparable unit. This means the crankshaft must always be replaced as a complete unit. The needle bearing (2) is replaceable on models MS 230 and MS 250.
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2
1
When fitting a replacement crankshaft, always install new ball bearings and oil seals.
– Remove the piston – b 6.6. : Remove the retaining ring
(arrow).
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: Pull off the oil seals (1) and ball bearings (2).
: Heat ball bearing to approx. 50°C (120°F) and, with closed side facing outwards, push it on to the crankshaft stub as far as stop. If the crankshaft has been removed, the oil seals used in production (9639 003 1585 with rigid housing)
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may be installed.
– Lubricate sealing lips of oil seals with grease – b 13.
: Slide oil seals over the crankshaft stubs so that their open sides are facing the ball bearings.
– Install new retaining ring in crankshaft groove.
– Install the piston – b 6.6.
V A 13 5R A 10 1
– Remove the front handle – b 9.2.
: Use standard 13 mm socket to unscrew the decompression valve.
– Install new decompression valve and torque down to 14 Nm (10.5 lbf.ft).
– Refit the front handle.
Exercise extreme caution when troubleshooting and carrying out maintenance or repair work on the ignition system. The high voltages which occur can cause serious or even fatal accidents!!
Troubleshooting on the ignition system should always begin at the spark plug – b 4.4.
The electronic (breakerless) ignition system basically consists of an ignition module (1) and flywheel (2).
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1
2
– Remove the air filter – b 11.1. – Pull out the shutter – b 5.3. – Pull boot off the spark plug. The ignition lead is molded to the module.
: Use pliers to grip the leg spring and pull it out of the spark plug boot.
– Unhook the leg spring from the ignition lead.
– Pull the spark plug boot off the
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ignition lead.
– Coat end of the ignition lead (about 20 mm/3/4") with oil. – Fit spark plug boot over the
ignition lead.
– Use pliers to grip the end of the ignition lead inside the spark plug boot and pull it out.
: Pinch the hook (arrow) of the leg spring into the center of the lead, i.e. about 10 mm (3/8") from the end of the lead.
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: Pull the lead back into the boot so that the leg spring locates properly inside it (see arrow). If the spark plug has a separate terminal nut, make sure that it is properly tightened down.
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– Fit boot on the spark plug. – Fit the shutter – b 5.3. – Install the air filter – b 11.1.
The ignition module accommodates all the components required to control ignition timing. There are two electrical connections on the coil body:
: the high voltage output with ignition lead (1),
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2
1
: the connector tag (2) for the short circuit wire.
Accurate testing of the ignition module is only possible with a special tester. For this reason it is only necessary to carry out a spark test in the workshop.
A new ignition module must be installed if no ignition spark is obtained (after checking that wiring and stop switch are in good condition).
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 ignition timing. Before starting the test, check that the spark plug is in good condition. Test the ignition coil only with the spark plug properly installed in the cylinder.
: Using the ZAT 4 ignition tester 5910 850 4503:
Pull the boot off the spark plug and connect it the input terminal (1). Push the tester’s output terminal (3) onto the spark plug. VA 208RA053
3
2
1
– Pull the rewind starter and check the sparkover in the tester’s window (2).
It is necessary to use the ZAT 3 ignition system tester
5910 850 4520 to test the auxiliary spark gap.
– Before starting the test, install a new spark plug in the cylinder and tighten it down firmly –
VA 208RA054 ZAT 3 5910 850 4520
3
2
1
b 3.5.: Pull the boot off the spark plug boot and connect it to
terminal (2).
: Attach ground terminal (1) (alligator clip) to spark plug. Use adjusting knob (3) to set spark gap to about 2 mm.
While using the ZAT 3, hold it only by the handle or position it in a safe place.
Warning!
High voltage – risk of electrocution. – Crank engine with rewind starter
(min. 1,000 rpm) and evaluate spark in spark window.
If a spark is visible, the ignition system is in order.
If no spark is visible, check the wiring harness and contact spring – b 7.4.
If the spark plug, ignition lead and spark plug boot are in order, use an ohmmeter to check the short circuit wire, ground wire and contact spring for a break.
: Pull the short circuit wire (arrow) off the tag on the ignition module. – Connect ohmmeter to ground
and the short circuit wire. – Set Master Control lever to "0".
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The measured resistance must be about 0 Ohm. If the reading is much higher, there is a break in the wire and the wire or Master Control lever must be replaced.
– Set Master Control lever to "1". The measured resistance must be infinitely high. If not, install a new Master Control lever.
7.3 Testing the
If no fault is found, perform the following additional checks: – Check flywheel for damage –
b 7.4.2.
– Check air gap between flywheel and ignition module – b 7.5. If no fault is detected in these areas either, install a new ignition module – b 7.4.2.
Ignition timing is not adjustable. Since there is no mechanical wear in these systems, ignition timing cannot get out of adjustment. However, an internal fault in the circuit can alter the switching point in such a way that a spark test will still show the system to be in order although timing is outside the permissible tolerance. This will impair engine starting and running
behavior. – Remove the fan housing –
b 8.2.
: Pull the short circuit wire off the tag on the ignition module.
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: Take out the screws (arrows).
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– Pull the ignition module forward a little.
: Take the short circuit wire (1) out of the retainer (2).
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2
1
: Push baffle plate (1) in direction of fanwheel and carefully pull out the ignition lead (2).
– Place the module in position, insert the screws but do not tighten them down yet.
: Secure ground wire (1) with outer screw.
: Slide the setting gauge (2) 1111 890 6400 between the arms of the ignition module and the flywheel magnet poles.
– Press the ignition module against the setting gauge and tighten down the mounting screws to 4 Nm (3 lbf.ft).
Reassemble all other parts in the reverse sequence.
Removing the flywheel:
– Fit the locking strip to block the piston – b 5.3.
– Remove the fan housing – b 8.2.
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– Unscrew the flywheel nut. – Pull off the flywheel.
If the flywheel cannot be removed by hand, screw on the puller (1) 1116 893 0800 and tap its end to release the flywheel. Remove the puller.
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1
Inspect flywheel (1) and magnet poles (2) for cracks or other damage. If you find any damage, install a new flywheel.
Installing the flywheel:
Degrease crankshaft stub and bore in flywheel with STIHL cleaner – b 13.
– Fit the flywheel. Check position of slot.
Assemble all other parts parts in the reverse sequence.
– Tighten the flywheel nut to 28 Nm (20.6 lbf.ft).
7.6 Ignition System Troubleshooting
Engine does not run
Master Control lever/slide control or separate stop switch
in position "1"?
Check the spark plug: – Smeared with oil, black?
– Sooted? – Electrode gap correct?
– Contacts shorted? Clean the plug, reset
or replace
Check spark plug boot: Firmly seated on plug (leg spring)? Leg spring hook in center of ignition lead?
Boot damaged?
If necessary, install new spark plug boot and/or leg spring
Test ignition system with ZAT 3 or ZAT 4 (use ZAT 3 as main spark gap
– see TI 32.94)
Check flywheel:
– Have pole shoes turned blue? Install new flywheel
Check air gap and reset if necessary
Check ignition lead: – Severe chafing? – Spark plug boot: Holes/cracks? – Resistance spark plug boot to ground:
spec. 1.5 – 12kΩ
– Check resistance of ignition lead:
spec. < 10Ω,
If necessary, install new spark plug boot and/or ignition lead
Disconnect short circuit wire from ignition module
1
3
yes no Powerful spark?2
Check ON/STOP function on Master Control lever/
slide contro or separate stop switch
no Install new
ignition module
yes
no
Look for fault in fuel system or carburetor, check engine for leaks, check position of flywheel on
crankshaft yes Check operation of
Master Control lever/slide control or separate stop switch – Short circuit wire chafed? – Contact gap (contact springs) If necessary, install new ignition lead
and/or contact springs Re-connect short circuit wire
2
3
Powerful spark?
Engine runs
If the action of the starter rope becomes very stiff and the rope rewinds very slowly or not
completely, it can 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. In such a case it is sufficient to apply a few drops of paraffin (kerosine) to the rewind spring.
Carefully pull out the starter rope several times and allow it to rewind until its normal smooth action is restored.
If clogged with dirt or pitch, the entire starter mechanism, including the rewind spring, must be removed and disassembled. Take special care when removing the spring. Wash all parts in STIHL cleaner. Lubricate the rewind spring and starter post with STIHL special lubricant, b 13, before installing.
: Remove the screws (arrows) from the fan housing and hand guard.
– Lift away the fan housing with rewind starter.
Reassemble in the reverse
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sequence.
– Tighten down screws to 6 Nm (4.4 lbf.ft).
Troubleshooting chart – b 4.2. – Remove the fan housing –
b 8.2.
Relieving tension of rewind spring:
The rewind spring will not be under tension if the starter rope is broken. – Pull out the starter rope about
5 cm (2") and hold the rope rotor steady.
– While still holding the rope rotor steady, take three full turns off the rope rotor.
– Pull out the rope with the starter grip and slowly release the rope rotor.
Removing the rope rotor: : Use a screwdriver or suitable
pliers to carefully remove the spring clip from the starter post.
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8. Rewind Starter
: Remove the washer (arrow).
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: Carefully pull the rope rotor off the starter post.
– To replace the rope rotor, first remove the starter rope – b 8.5.
The rewind spring may pop out and
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unwind if rope rotor is not removed very carefully.
Installing the rope rotor:
Coat bore in rope rotor with STIHL special lubricant – b 13.
: Fit the rotor on the starter post so that the lug (1) on the rope rotor slips behind the inner spring
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1
2
loop (2).
Check that spring loop has engaged by turning rope rotor slightly and letting it go – it must spin back.
– Fit washer and push the spring clip into the groove in the starter post.
Make sure the spring clip (1) engages the pawl guide peg (2) and points in the clockwise direction.
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2
1
VA
The spring clip must be handled very carefully. If it is bent during disassembly or assembly, the rewind starter may not function properly.
– Install the starter rope – b 8.5. – Tension the rewind spring –
– Remove the rope rotor – b 8.3.
: Use a screwdriver to pry the segment (1) out of the upper retainers (4).
– Pull the segment upwards and remove.
Reassemble in the following sequence.
: Place the segment (1) in position and push it under the retainer (2). : Engage lugs (3) flush with
housing.
: Push segment into retainers (4). Reassemble all other parts in the reverse sequence.
Remove the rope rotor – b 8.3. – Remove the remaining rope from
the rope rotor and the starter grip.
: Thread end of new rope through the hole in the side of the rotor, pull it out.
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– Secure the rope with a simple overhand knot.
: Pull the rope back until the knot locates in the recess (arrow) in
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: Thread the other end of the rope through the guide bush from inside.
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: Then through the underside of the starter grip and pull it out.
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2
08RA0039
: Tie one of the special knots shown.
– Pull the rope back into the starter grip.
– Install the rope rotor – b 8.3.
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– Tension the rewind spring – b 8.5.2.
: Pry the nipple of the starter rope out of the starter grip. Pull out the starter rope.
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: Thread new starter rope through the top of the starter grip.
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: Thread the other end of the rope, from outside, through the guide bush in the fan housing.
– Fit the rope in the rope rotor – b 8.5.
– Install the rope rotor – b 8.3.
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– Fit the fan housing – b 8.2.
: Pull out the starter rope until the nipple (1) locates in the starter grip.
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1
: Make a loop in the starter rope.
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: Grip the rope next to the rotor and use it to turn the rope rotor six times clockwise.
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: Hold the rope rotor steady. : Pull out the rope with the starter
grip and straighten it out.
– Hold the starter grip firmly to keep the rope tensioned.
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– Let go of the rope rotor and slowly release the starter rope so that it can rewind properly.
The rewind spring is correctly tensioned when the starter grip sits firmly in the rope guide bush without drooping to one side. If this is not the case, tension the spring by one additional turn.
When the starter rope is fully
V A 13 5R A 12 2
extended, it must still be possible to rotate the rope rotor at least another half turn before maximum spring tension is reached. If this is not the case, pull the rope out, hold the rope rotor steady and take off one turn of the rope.
Do not overtension the rewind spring as this will cause it to break.
– Fit the fan housing – b 8.2.
– Remove the rope rotor – b 8.3. The replacement spring comes ready for installation and is secured with a frame.
– Lubricate the spring with a few drops of STIHL special lubricant before installation – b 13. : The frame (1) slips off as the
rewind spring is pushed into the fan housing.
Press the anchor loop (2) into the recess in the fan housing at the same time.
The rewind spring may pop out and uncoil during installation.
– If the rewind spring has popped out, refit it in the assembly tool 1116 893 4800 as follows:
: Position the anchor loop about 20 mm (3/4") (dimension 'a') from the edge of the assembly tool.
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1 a
: Fit the rewind spring in the counterclockwise direction, starting from outside and working inwards.
– Place wooden block 1108 893 4800 over the assembly tool to simplify this
V A 1 4 3 R A 1 22 operation.
– Slip the assembly tool with rewind spring over the starter post.
: Push the rewind spring into the fan housing and then remove the assembly tool.
– Install the rope rotor – b 8.3. – Tension the rewind spring –
b 8.6.
: Remove the spring clip (1) from the starter post.
Do not take the rope rotor off the starter post.
: Pull the pawl (2) out of the rope rotor.
2
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1
– Coat peg of new pawl with graphite grease – b 13. Reassemble in the reverse sequence.
Rubber anti-vibration buffers are installed between the handle and engine housing, handle housing and front handle. Damaged rubber buffers (annular buffers) must always be replaced.
Annular buffers in front handle – Remove the front handle –
b 9.2.
: Pry both annular buffers out of the front handle.
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: Push home the annular buffer from inside the front handle until its groove (1) engages over the housing rib (2).
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2
1
Annular buffer in engine housing – Front handle removed.
: Pry the annular buffer out of the engine housing.
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V
A
: Push annular buffer into the engine housing until its groove engages over the housing rib. – Fit the front handle.
V A 13 5R A 12 6
Annular buffer in handle housing – Remove the handle housing –
b 9.3.
135RA127
V
A
8.7 Pawl 9. AV Handle System/
Handle Housing
: Pry the annular buffer out of the handle housing.
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V
A
: Push the annular buffer into the handle housing from outside until its groove (1) engages over the rib (2).
– Install the handle housing – b 9.3.
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2 1
: Take the lower mounting screws out of the front handle.
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– Remove lower bumper strip from the tensioner.
: Ease plugs out of the annular buffers.
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V
A
: Take out the screws.
: Pull the lower part of the handle housing out of the front handle. – Remove the front handle. Reassemble in the reverse sequence.
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– Tighten down screws in annular buffers to 3.5 Nm (2.6 lbf.ft).
– Remove the front handle – b 9.2.
– Remove the fan housing – b 8.2.
– Remove the muffler – b 6.1. – Remove the carburetor –
b 11.2.2.
: Disconnect tank vent hose from the stub.
: Pull the ground wire (1) off the contact spring.
: Pull the short circuit wire's contact sleeve (2) out of the
135RA135
V
A
1
2
: Ease the plug out of the annular buffer.
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V
A
: Pry the annular buffer out of the engine housing.
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V
A
: Pull the handle housing slightly forward and push the manifold through the handle housing opening at the same time.
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V
A
: Push the grommet out of the handle housing.
– Pull the ground and short circuit wires out of the bore.
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V
A
: Pull the impulse hose off the stub on the handle housing.
V A 1 3 5 R A 1 4 0 9.3 Handle Housing
: On easy start machines, pull manual fuel pump hose (arrow) out of the fuel tank.
– Remove the handle housing. – To replace, remove the annular
buffers – b 9.1.
– Remove the switch shaft – b 9.4.
– Remove the throttle trigger – b 9.6.
– Remove the contact spring – b 9.5.
– On easy start machines, remove the manual fuel pump – b 11.6. Reassemble in the reverse
sequence.
: To fit the manifold in the handle housing intake opening, wind a piece of string (about 15 cm / 6" long) around the back of the manifold flange.
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: Place the handle housing in position and pass the string (1), fuel hose (2), ground wire (3) and short circuit wire (4) through the openings. VA 135RA143 4 3 2 1
: Push the grommet for the ground and short circuit wires into the bore from inside.
: Connect the impulse hose to the stub on the handle housing.
: Pull the ends of the string outward.
The manifold flange is thus pulled through the handle housing intake opening without any damage to the manifold.
: Push the annular buffer into the engine housing until its groove engages over the housing rib. Reassemble all other parts in the reverse sequence.
VA
– Remove the carburetor box cover – b 11.1.
: Pull the contact sleeve out of the switch shaft.
: Move the Master Control lever (1) until the slot in the choke shaft (2) and the choke rod (3) are in line.
: Pull the choke rod out of the switch shaft and the choke shaft.
: Set the Master Control lever to the horizontal position and pry the switch shaft out of its pivot mount.
: Pull the switch shaft out of its bore.
Install in the reverse sequence.
: Lift the contact spring slightly to install the switch shaft.
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– Remove the carburetor – b 11.2.2.
: Pull the ground wire terminal off the contact spring.
: Pull the contact spring out its seat in the handle housing.
Install in the reverse sequence.
– Remove the carburetor box cover – b 11.1.
: Take out the screw.
– Swing the handle molding up and lift it away.
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– Move the Master Control lever to the normal "RUN" position. : Pull the interlock lever out of its
seat.
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: Remove the throttle rod from the throttle trigger.
: Use a 4 mm (5/32") drift to drive out the cylindrical pin (1). : Remove the throttle trigger (2)
and torsion spring (3).
: Take the torsion spring off the throttle trigger.
: Fit the throttle trigger so that the seat for the throttle rod points upward.
: Use a 4 mm (5/32") drift to push
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: Push the throttle rod into the throttle trigger.
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: Press the interlock lever into the slots. The torsion spring must be under the interlock lever and engage the notch.
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: Press the interlock lever (1) downward.
: Push the throttle trigger upward and move the Master Control
2 1
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9.6 Throttle Trigger/
: Fit the handle molding so that it engages behind the lugs as shown.
– Insert screw and tighten down to 1.6 Nm (1.2 lbf.ft).
– Fit the carburetor box cover –
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b 11.1.
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. In the event of problems with the oil supply system, first check the oil tank and the pickup body. Clean the oil tank if necessary.
Troubleshooting chart – b 4.3. – Unscrew oil filler cap and drain
the oil tank.
Collect chain oil in a clean container or dispose of it properly at an approved disposal site.
– Observe safety precautions – b 2.
: Use hook (1) 5910 893 8800 to withdraw the pickup body from the oil tank.
Avoid stretching the oil suction
: Pull the pickup body out of the oil suction hose.
– Wash the pickup body in STIHL cleaner and, if possible, blow out with compressed air.
– Replace pickup body if it is
V A 13 5R A 16 5 damaged.
– Flush out the oil tank.
Install in the reverse sequence.
10. Chain Lubrication
– Remove the front handle – b 9.2.
: Take out the screw.
VA
135RA166
: Pull the connector out of the oil pump and suction hose.
VA
135RA167
: Pull suction hose with pickup body out of the oil tank. – Remove the pickup body.
VA
135RA168
Install in the reverse sequence. : Fit new O-ring on connector
(see arrow).
– Tighten down screw to 4.0 Nm (3.0 lbf.ft).
VA
208RA017
A vent valve is installed in the tank wall to keep the internal pressure in the oil tank equal to atmospheric pressure.
Cleaning the valve
– Unscrew the oil filler cap. – Drain the oil tank.
Collect chain oil in a clean container or dispose of it properly at an approved disposal site.
– Observe safety precautions – b 2.
– Use compressed air to blow valve clear from the outside inwards. – Flush the oil tank.
– Fit the oil filler cap.
Replacing the valve – Unscrew the oil filler cap.
: Use a 5 mm (3/16") dia. drift to carefully drive the valve out of the housing from inside the tank.
VA
135RA170
10.2 Connector/
: Use a 7 mm (9/32") dia. drift to carefully push home the new valve until dimension 'a' is about 1 mm (3/64").
– Fit the oil filler cap.
VA
176RA243
a
– Remove the clutch – b 8. : Remove the cover washer (1).
VA
208RA018
1
: Pull the worm and drive spring (arrow) off the crankshaft stub.
: Take the drive spring off the worm.
Reassemble in the reverse sequence.
Fit the cover washer so that the word "TOP" faces outwards.
Removing
– Remove the connector – b 10.2.
: Pry out the lower annular buffer.
VA
135RA173
: Fit lever (1) of installing tool 1123 890 2201 in the bore for the annular buffer – from inside.
VA
135RA174
1
: Screw fork head (1123) with threaded stem (from installing tool) into the oil pump.
VA
135RA175
: Swing lever (1) down into fork head (2) and secure it with the connecting pin (3). V A 13 5R A 17 6 1 2 3
: Swing lever upward to pull the oil pump out of the housing.
– Unscrew the oil pump from the fork head.
VA
135RA177
Installing
: Place the oil pump in position so that its groove (1) lines up with the square (2) on the housing.
V A 13 5R A 17 8 1 2
: Place the fork head (1123/01) with the straight stem (from installing tool) in the oil pump. – Fit lever in fork head and secure
in position.
: Press the lever down until the fork head butts against the engine housing. The oil pump is now installed at the right depth. – Remove the lever.
: Push the annular buffer into the housing until its groove engages over the housing rib.
– Fit the connector – b 10.2.
Dirty air filters reduce engine power, increase fuel consumption and make starting more difficult. The air filter should always be cleaned when there is a
noticeable loss of engine power. – Close the choke shutter.
: Turn twist lock (1) 90 degrees counterclockwise.
: Lift off the carburetor box cover (2) vertically.
– Remove all loose dirt from around the filter.
VA
208RA019
1
2
Fabric/fleece filter
: Place fingers behind the filter, press thumbs against housing, and swing filter toward rear handle.
– Remove the filter.
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135RA199
– Use compressed to blow out filter from the clean air side.
– If the filter is caked with dirt or no compressed air is available, wash the filter in a fresh, non-flammable cleaning solution (e.g. warm soapy water) and then dry. Replace a damaged air filter.
: To remove the filter housing, unscrew the nuts (1 and 2) and lift the filter housing away. Reassemble in the reverse sequence.
VA
208RA023
1
2
– Tighten down nuts to 2.7 Nm (2.0 lbf.ft).
– Push air filter onto filter housing until it snaps into position.
11. Fuel System