Stihl BR 800 User manual

|
2018-06
STIHL BR 800 Service Manual

Printed on chlorine-free paper Printing inks contain vegetable oils, paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2018 RA_014_2018_01_01. VA0.F18. 0000008149_003_GB
BR 800 1
{This service manual is protected by copyright. All rights reserved, especially the rights to reproduce, translate and process with electronic
systems.
Contents
1 About this Service Manual 3
1.1 Applicable Documentation 3
1.2 Symbols in Text 3
2 Safety During Repair Work 3
2.1 Protective Gloves 3
2.2 Safety Glasses 3
2.3 Spare Parts 3
3 Preparations for Repair 3
3.1 Preparing the Blower 3
4 Troubleshooting 4
4.1 Blower wheel runs while engine is idling: 4
4.2 Starter rope does not rewind 4
4.3 Starter rope cannot be pulled out far enough 4
4.4 Starter rope can be pulled out almost without
resistance (crankshaft does not turn) 4
4.5 Starter rope is difficult to pull or rewinds very
slowly 5
4.6 Engine does not run or runs erratically, with
misfiring and sporadic loss of power 5
4.7 Engine will not idle, idle speed too high 6
4.8 Engine stops when throttle trigger is released 6
4.9 Engine does not start easily, stalls at idle
speed, but operates normally at full throttle 7
4.10 Engine does not deliver full power or runs
erratically 7
4.11 Engine does not start. 8
4.12 Engine speed drops quickly under load – low
power 8
4.13 No spark 9
4.14 Engine stops suddenly 10
4.15 Engine does not reach maximum RPM. 11
5 Harness 12
5.1 Tools, Servicing Aids 12
5.2 Removing the Harness 12
5.3 Fitting the Harness 13
5.4 Removing the Backplate Extension 13
5.5 Fitting the Backplate Extension 13
6 Rewind Starter 14
6.1 Tools, Servicing Aids 14
6.2 Removing the Rewind Starter 14
6.3 Removing the Bearing Shell 14
6.4 Relieving Tension of Rewind Spring 14
6.5 Removing the Spring Housing 14
6.6 Removing the Rewind Spring 15
6.7 Removing the Starter Rope 15
6.8 Installing the Starter Rope 15
6.9 Installing the Rewind Spring 15
6.10 Installing the Rope Rotor 16
6.11 Installing the Spring Housing 16
6.12 Tensioning the Rewind Spring. 17
6.13 Installing the Bearing Shell 17
6.14 Installing the Rewind Starter 18
6.15 Removing the Stop Buffers 18
6.16 Installing the Stop Buffers 18
7 Air Filter, Shroud 19
7.1 Tools, Servicing Aids 19
7.2 Removing the Air Filter 19
7.3 Installing the Air Filter 19
7.4 Removing the Shroud 19
7.5 Installing the Shroud 19
8 Filter Housing, Carburetor, Fuel Pump 20
8.1 Tools, Servicing Aids 20
8.2 Removing Filter Housing and Carburetor 20
8.3 Installing Filter Housing and Carburetor 20
8.4 Removing the Fuel Pump 21
8.5 Installing the Fuel Pump 22
8.6 Removing the Baffle 22
8.7 Installing the Baffle 22
9Carburetor 23
9.1 Special Servicing Tools, Servicing Aids 23
9.2 Testing Carburetor for Leaks 23
9.3 Disassembling the Carburetor 24
9.4 Assembling the Carburetor 25
9.5 Adjusting the Carburetor 27
10 Backplate, Tank Housing 29
10.1 Tools, Servicing Aids 29
10.2 Removing Pickup Body from Fuel Tank 29
10.3 Installing Pickup Body in Fuel Tank 29
10.4 Testing the Tank Vent 29
10.5 Removing the Fuel Tank 30
10.6 Installing the Fuel Tank 30
10.7 Removing the Tank Vent 30
10.8 Installing the Tank Vent 30
10.9 Removing the Backplate 30
10.10 Removing the Protective Screen 30
10.11 Fitting the Protective Screen 31
10.12 Installing the Backplate 31
11 Antivibration Elements 32
11.1 Tools, Servicing Aids 32
11.2 Removing the Antivibration Elements 32
11.3 Installing the Antivibration Elements 32
11.4 Removing the Stop Buffer 32
11.5 Installing the Stop Buffer 33
12 Adjusting Valve Clearance 34
12.1 Tools, Servicing Aids 34
12.2 Checking, Adjusting Valve Clearance 34
13 Ignition System 36
13.1 Special Servicing Tools, Servicing Aids 36

BR 8002
13.2 Testing the Ignition System 36
13.3 Removing the Flywheel 37
13.4 Installing the Flywheel 37
13.5 Removing the Ignition Module 38
13.6 Disassembling the Spark Plug Boot 38
13.7 Assembling the Spark Plug Boot 38
13.8 Installing the Ignition Module 38
14 Airflow Shroud, Impulse Hose, Manifold 39
14.1 Tools, Servicing Aids 39
14.2 Removing the Airflow Shroud 39
14.3 Installing the Airflow Shroud 39
14.4 Removing the Impulse Hose 40
14.5 Installing the Impulse Hose 40
14.6 Removing the Manifold 40
14.7 Installing the Manifold 40
15 Control Handle 41
15.1 Special Servicing Tools, Servicing Aids 41
15.2 Removing the Control Handle 41
15.3 Fitting the Control Handle 41
15.4 Removing the Clamp 43
15.5 Installing the Clamp 43
15.6 Removing the Throttle Cable 43
15.7 Installing the Throttle Cable 43
16 Muffler 44
16.1 Tools, Servicing Aids 44
16.2 Removing the Muffler 44
16.3 Installing the Muffler 44
16.4 Removing the Scoop and Spark Arrestor 44
16.5 Installing the Scoop and Spark Arrestor 44
17 Blower Assembly 45
17.1 Tools, Servicing Aids 45
17.2 Removing the Stop Buffer 45
17.3 Installing the Stop Buffer 45
17.4 Removing Outer Blower Housing and Elbow 45
17.5 Removing the Blower Wheel 45
17.6 Removing the Inner Blower Housing 46
17.7 Installing the Inner Blower Housing 46
17.8 Installing the Blower Wheel 46
17.9 Installing Outer Blower Housing and Elbow 46
18 Valve Gear 47
18.1 Tools, Servicing Aids 47
18.2 Removing Rocker Arms and Pushrods 47
18.3 Removing Cam Followers and Cam Gear 48
18.4 Checking Decompression System 48
18.5 Installing Cam Followers and Cam Gear 48
18.6 Installing Rocker Arms and Pushrods 48
19 Testing Engine for Leaks 50
19.1 Tools, Servicing Aids 50
19.2 Testing Compression Pressure 50
19.3 Testing Engine for Leaks 50
20 Crankcase, Crankshaft, Oil Seals 52
20.1 Tools, Servicing Aids 52
20.2 Removing the Collar Studs 52
20.3 Installing the Collar Studs 52
20.4 Removing the Engine Pan and Oil Seals 52
20.5 Removing Crankshaft with Piston 53
20.6 Removing the Piston 53
20.7 Installing the Piston 53
20.8 Installing Crankshaft with Piston 54
20.9 Removing Valves and Valve Springs 54
20.10 Installing Valves and Valve Springs 54
20.11 Installing the Engine Pan and Oil Seals 55
21 Tools, Servicing Aids 56
21.1 Tools, Servicing Aids 56

BR 800 3
1.1 Applicable Documentation
NPlease observe the following documentation in
addition to this service manual.
–Spare parts documentation
–TI bulletins
–Instruction manual
1.2 Symbols in Text
2.1 Protective Gloves
Sharp or hot components can cause cuts or burns.
NIf sharp or hot components have to be handled during
a repair: Wear protective gloves.
2.2 Safety Glasses
Particles and objects can be thrown into the air at high
speed during a repair. Thrown particles or objects can
cause eye injuries.
NIf there is a risk of particles being thrown during the
repair: Wear safety glasses.
2.3 Spare Parts
If spare parts not approved by STIHL are installed, they
may not fulfill the required function or deactivate safety
devices. This can result in serious or fatal injuries.
NSTIHL recommends the use of genuine STIHL
replacement parts.
3.1 Preparing the Blower
NDrain the fuel tank into a container approved for fuels.
NClean the blower.
1 About this Service Manual
This symbol refers to a chapter in this service
manual.
A video is available for this chapter
This symbol shows the tightening torque for a
screw joint and the procedure after tightening.
In this example: Tightening torque 5 Nm. Then
rotate 1 full turn counterclockwise.
2 Safety During Repair Work
3 Preparations for Repair
5 Nm
1

BR 8004
4.1 Blower wheel runs while engine is idling:
4.2 Starter rope does not rewind
4.3 Starter rope cannot be pulled out far enough
4.4 Starter rope can be pulled out almost without
resistance (crankshaft does not turn)
4 Troubleshooting
The following tables are intended to identify problems and remedy malfunctions. Always start troubleshooting at line 1 of
the table and work through the questions one by one.
Check the following Yes No
1. Is idle speed setting correct? Repair completed. If MDG 1 analyzer is available: Adjust
carburetor with MDG 1 analyzer, @
9.5.
If MDG 1 analyzer is not available:
Adjust carburetor with
EDT 8 tachometer, @ 9.5.
Repair completed.
Check the following Yes No
1. Is rewind spring broken? Replace rewind spring, @ 6.6.
Go to 2.
Go to 2.
2. Is rewind spring very dirty or rusted? Clean or replace the rewind spring, @
6.6.
Go to 3.
Go to 3.
3. Is rewind spring properly tensioned? Replace rewind starter, @ 6.2.
Repair completed.
Increase tension of rewind spring, @
6.12.
Repair completed.
Check the following Yes No
1. Is tension of rewind spring too high? Reduce tension of rewind spring.
Repair completed.
Replace rewind starter, @ 6.2.
Repair completed.
Check the following Yes No
1. Is the spring on the rope rotor
fatigued?
Fit new spring on rope rotor, @ 6.6.
Go to 2.
Go to 2.
2. Are pawls on the rope rotor damaged
or badly worn?
Fit new pawls on rope rotor, @ 6.6.
Repair completed.
Replace rewind starter, @ 6.2.
Repair completed.

BR 800 5
4.5 Starter rope is difficult to pull or rewinds very
slowly
4.6 Engine does not run or runs erratically, with misfi-
ring and sporadic loss of power
Check the following Yes No
1. Is the rewind starter clean? Go to 2. Clean starter mechanism
Go to 2.
2. Are windings of rewind spring stuck
together?
Coat rewind spring with standard sol-
vent-based degreasant containing no
chlorinated or halogenated hydrocar-
bons. Pull starter rope several times
until normal action is restored
Repair completed.
Replace rewind starter, @ 6.2.
Repair completed.
Check the following Yes No
1. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 2.
2. Test ignition system with ZAT 3 or
ZAT 4, @ 13.2.
Sparkover?
Go to 19. Go to 3.
3. Is correct spark plug installed? Go to 4. Install correct spark plug.
Go to 4.
4. Is spark plug sooted or smeared with
oil?
Clean or replace the spark plug.
Go to 5.
Go to 5.
5. Is spark plug electrode gap correct? Go to 6. Set electrode gap correctly.
Go to 6.
6. Is spark plug boot damaged? Replace spark plug boot, @ 13.6.
Go to 7.
Go to 7.
7. Check resistance: spark plug boot to
ground.
Is resistance of spark plug boot to
ground 1.5 kΩ to 12 kΩ?
Go to 8. Replace ignition lead, @ 13.6.
Go to 8.
8. Leg spring hook in center of ignition
lead?
Go to 9. Replace spark plug boot, @ 13.6.
Go to 9.
9. Air gap between ignition module and
flywheel correct?
Go to 10. Set air gap correctly, @ 13.7.
Go to 10.
10. Is black wire of wiring harness
chafed?
Replace throttle cable with wiring har-
ness, @ 14.2 and @ 15.2.
Go to 11.
Go to 11.
11. Is insulation on connector of wiring
harness’ black wire in order?
Go to 12. Replace throttle cable with wiring har-
ness, @ 14.2 and @ 15.1.
Go to 12.
12. Is connector of wiring harness’ black
wire firmly seated?
Go to 13. Push connector of wiring harness’
black wire firmly into place, @ 14.3.
Go to 13.
13. Is ignition lead chafed? Replace ignition lead, @ 13.5.
Go to 14.
Go to 14.

BR 8006
4.7 Engine will not idle, idle speed too high
4.8 Engine stops when throttle trigger is released
14. Check resistance of ignition lead.
Is resistance of ignition lead less than
10 Ω?
Go to 15. Replace ignition lead, @ 13.5.
Go to 15.
15. Is flywheel damaged? Replace flywheel, @ 13.3.
Go to 16.
Go to 16.
16. Have pole shoes turned blue? Replace flywheel, @ 13.3.
Go to 17.
Go to 17.
17. Is spline in flywheel hub in place and
undamaged?
Go to 18. Replace flywheel, @ 13.3.
Go to 18.
18. Test ignition system with ZAT 3 or
ZAT 4, @ 13.2.
Sparkover?
Go to 19. Replace ignition lead, @ 13.5.
Go to 19.
19. Does condition still exist? Look for fault in fuel system, test
engine for leaks, @ 19.3.
Repair completed.
Repair completed.
Check the following Yes No
Check the following Yes No
1. Test engine for leaks, @ 19.3.
Are oil seals or the crankcase
leaking?
Replace oil seals, @ 20.4 or seal up
or replace crankcase, @ 20.4.
Go to 2.
Go to 2.
2. Is throttle cable stiff? Replace throttle cable, @ 14.2 and
@ 15.2.
Repair completed.
Replace carburetor, @ 8.2.
Repair completed.
Check the following Yes No
1. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 2.
2. Remove air filter and install new air
filter.
Does condition still exist?
Reinstall the old air filter.
Go to 3.
Clean old air filter properly or fit new
filter.
Repair completed.
3. Piston seizure? Replace cylinder and piston, @ 20.5.
Go to 4.
Go to 7.
4. Is throttle shutter fully closed? Go to 5. Adjust throttle shutter correctly, @
9.4.
Go to 5.
5. Test tank vent, @ 10.4.
Is tank vent OK?
Go to 6. Fit new tank vent, @ 10.7.
Go to 6.
6. Is fuel system leaking? Replace fuel hoses, @ 8.2.
Repair completed.
Replace carburetor, @ 8.2.
Repair completed.

BR 800 7
4.9 Engine does not start easily, stalls at idle speed,
but operates normally at full throttle
4.10 Engine does not deliver full power or runs erratical-
ly
Check the following Yes No
1. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 2.
2. Piston seizure? Replace cylinder and piston, @ 20.5.
Go to 3.
Go to 3.
3. Test engine for leaks, @ 19.3.
Are oil seals, manifold or crankcase
leaking?
Replace oil seals or seal up or replace
crankcase, @ 20.4.
Repair completed.
Repair completed.
Check the following Yes No
1. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 2.
2. Remove air filter and install new air
filter.
Does condition still exist?
Reinstall the old air filter.
Go to 3.
Clean old air filter properly or fit new
filter.
Repair completed.
3. Is decompression system in order? Go to 4. Check decompression system. If the
decompression system is damaged:
Install new cam gear, @ 18.3.
Go to 4.
4. Is pickup body in oil tank dirty? Replace pickup body in fuel tank, @
10.2.
Go to 5.
Go to 5.
5. Is fuel system leaking? Replace fuel hoses, @ 8.2.
Go to 6.
Go to 6.
6. Is correct spark plug installed? Go to 7. Install correct spark plug.
Go to 7.
7. Is spark plug dirty or damaged? Clean or replace the spark plug.
Go to 8.
Go to 8.
8. Is spark plug electrode gap correct? Go to 9. Set electrode gap correctly.
Go to 9.
9. Are muffler, cylinder exhaust port or
spark arrestor (if fitted) carbonized?
Clean cylinder exhaust port, muffler
inlet and exhaust or replace muffler,
@ 16.2, replace spark arrestor, @
16.4.
Go to 102.
Go to 10.
10. Piston seizure? Replace cylinder and piston, @ 20.5
and @ 20.6.
Go to 11.
Go to 11.
11. Are air inlets in blower housing
blocked, is pre-separator plugged or
are cylinder fins very dirty?
Clean all cooling air inlets, pre-sep-
arator and cylinder fins
Go to 12.
Go to 12.

BR 8008
4.11 Engine does not start.
4.12 Engine speed drops quickly under load – low po-
wer
13. Piston rings broken? Install new piston rings, @ 20.6.
Go to 14.
Go to 14.
14. Is carburetor setting correct? Go to 15. Go to 15.
15. Does condition still exist? Replace carburetor, @ 8.2.
Repair completed.
Repair completed.
Check the following Yes No
Check the following Yes No
1. Is spark plug damp? Go to 2. Go to 4.
2. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 4.
3. Create diagnostic report.
Does condition still exist?
Go to 4. Repair completed.
4. Does carburetor choke shutter close
fully?
Go to 5. Replace carburetor, @ 8.2.
Go to 5.
5. Is fuel system leaking? Replace fuel hoses, @ 8.2.
Go to 6.
Go to 6.
6. Break in one wire in wiring harness? Replace throttle cable with wiring har-
ness, @ 14.2 and @ 15.2.
Go to 7.
Go to 7.
7. Are cable lugs on wiring harness and
screws on cylinder dirty?
Clean cable lugs on wiring harness
and screws on cylinder.
Go to 8.
Go to 8.
9. Test engine for leaks, @ 19.3.
Is engine OK?
Go to 10. Replace impulse hose, @ 14.4, man-
ifold, @ 14.6, piston rings or oil seals,
@ 20.4 or seal up or replace crank-
case, @ 20.4.
Go to 10.
10. Does condition still exist? Replace carburetor, @ 8.2.
Repair completed.
Repair completed.
Check the following Yes No
1. Is spark plug damp? Go to 2. Go to 4.
2. Is MDG 1 analyzer available? Go to 3. Go to 4.
3. Create diagnostic report.
Does condition still exist?
Go to 4. Repair completed.
4. Does throttle shutter open fully? Go to 5. Install throttle cable correctly or
replace, @ 14.2 and @ 15.2.
Go to 5.
5. Test tank vent, @ 10.4.
Is tank vent OK?
Go to 6. Fit new tank vent, @ 10.7.
Go to 6.
6. Is pickup body in oil tank dirty? Replace pickup body in fuel tank, @
10.2.
Go to 7.
Go to 7.

BR 800 9
4.13 No spark
7. Is fuel system leaking? Replace fuel hoses, @ 8.2.
Go to 8.
Go to 8.
8. Is impulse hose damaged or kinked? Replace impulse hose, @ 14.4.
Go to 9.
Decoke cylinder exhaust port and
spark arrestor (if fitted).
Go to 9.
9. Are muffler, cylinder exhaust port or
spark arrestor (if fitted) carbonized?
Clean cylinder exhaust port, muffler
inlet and exhaust or replace muffler,
@ 16.2, replace spark arrestor.
Go to 10.
Go to 10.
10. Is fuel strainer in carburetor dirty? Clean or replace carburetor, @ 8.2.
Go to 11.
Go to 11.
11. Is pump diaphragm distorted? Fit new pump diaphragm, @ 9.3.
Go to 12.
Go to 12.
12. Foreign matter in valve seal or on
cone of inlet needle?
Clean the carburetor
Go to 13.
Go to 13.
13. Inlet control lever sticking? Free off inlet control lever.
Go to 14.
Go to 14.
14. Is spring properly seated on inlet con-
trol lever?
Go to 15. Install inlet control lever properly, @
9.4.
Go to 16.
15. Is metering diaphragm distorted? Fit new metering diaphragm, @ 9.3.
Repair completed.
Replace carburetor, @ 8.2.
Repair completed.
Check the following Yes No
Check the following Yes No
1. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 2.
2. Is spark plug sooted or smeared with
oil?
Clean or replace the spark plug.
Go to 3.
Go to 3.
3. Is spark plug electrode gap correct? Go to 4. Set electrode gap correctly.
Go to 4.
4. Is spark plug boot damaged? Replace spark plug boot, @ 13.6.
Go to 5.
Go to 5.
5. Leg spring hook in center of ignition
lead?
Go to 6. Replace spark plug boot, @ 13.6.
Go to 6.
6. Is wiring harness chafed? Replace throttle cable with wiring har-
ness, @ 14.2 and @ 15.2.
Go to 7.
Go to 7.
7. Is insulation on wiring harness con-
nector in order?
Go to 8. Replace throttle cable with wiring har-
ness, @ 14.2 and @ 15.2.
Go to 8.
8. Is wiring harness connector firmly
seated?
Go to 9. Push wiring harness connector firmly
into place, @ 15.3, @ 8.3.
Go to 9.
9. Is ignition lead chafed? Install new ignition module, @ 13.5.
Go to 10.
Go to 10.
10. Is flywheel damaged? Replace flywheel, @ 13.3.
Go to 11.
Go to 11.

BR 80010
4.14 Engine stops suddenly
11. Air gap between ignition module and
flywheel correct?
Go to 12. Set air gap correctly, @ 13.8.
Go to 12.
12. Have pole shoes turned blue? Replace flywheel, @ 13.3.
Go to 13.
Go to 13.
13. Is spline in flywheel hub in place and
undamaged?
Go to 14. Replace flywheel, @ 13.3.
Go to 14.
14. Check resistance of ignition lead.
Is resistance less than 10 Ω?
Go to 15. Install new ignition module, @ 13.8.
Go to 15.
15. Check resistance: spark plug boot to
ground.
Is resistance between 1.5 kΩ and
12 kΩ?
Go to 16. Install new ignition module, @ 13.8.
Go to 16.
16. Test ignition system with ZAT 3,
ZAT 4 or MDG 1 analyzer, @ 13.8.
Sparkover?
Repair completed. Install new ignition module, @ 13.5.
Repair completed.
Check the following Yes No
Check the following Yes No
1. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 2.
2. Test tank vent, @ 10.4.
Is tank vent OK?
Go to 3. Fit new tank vent, @ 10.7.
Go to 3.
3. Is pickup body in oil tank dirty? Replace pickup body in fuel tank, @
10.2.
Go to 4.
Go to 4.
4. Is fuel system leaking? Replace fuel hoses, @ 8.2.
Go to 5.
Go to 5.
5. Break in one wire in wiring harness? Replace throttle cable with wiring har-
ness, @ 14.2 and @ 15.2.
Go to 6.
Go to 6.
6. Are cable lugs on wiring harness and
screws on cylinder dirty?
Clean cable lugs on wiring harness
and screws on cylinder.
Go to 7.
Go to 7.
7. Test ignition system with ZAT 3,
ZAT 4 or MDG 1 analyzer, @ 13.2.
Sparkover?
Go to 8. Go to 8.
8. Does carburetor choke shutter open
fully?
Go to 9. Replace carburetor, @ 8.2.
Go to 9.
9. Is spark plug damp? Go to 10. Go to 11.
10. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 11.
11. Test engine for leaks, @ 19.3.
Is engine OK?
Go to 12. Replace impulse hose, @ 14.4, man-
ifold, @ 14.6, piston rings or oil seals,
@ 20.4 or seal up or replace crank-
case, @ 20.5.
Go to 12.
12. Does condition still exist? Replace carburetor, @ 8.2.
Repair completed.
Repair completed.

BR 800 11
4.15 Engine does not reach maximum RPM.
Check the following Yes No
1. Is blower being used at high altitude? Blower ....
Go to 2.
Go to 2.
2. Is MDG 1 analyzer available? Create diagnostic report.
Test blower with MDG 1 analyzer.
Repair completed.
Go to 3.
3. Break in one wire in wiring harness? Replace throttle cable with wiring har-
ness, @ 14.2 and @ 15.1.
Go to 4.
Go to 4.
4. Are cable lugs on wiring harness and
screws on cylinder dirty?
Clean cable lugs on wiring harness
and screws on cylinder.
Go to 5.
Go to 5.
5. Test engine for leaks, @ 19.3.
Is engine OK?
Go to 6. Replace impulse hose, @ 14.4, man-
ifold, @ 14.6, piston rings or oil seals,
@ 20.4 or seal up or replace crank-
case, @ 20.5.
Go to 6.
6. Is fuel system leaking? Replace fuel hoses, @ 8.2.
Go to 7.
Go to 7.
7. Is maximum engine speed higher that
8,300 RPM
Repair completed. Replace carburetor, @ 8.2.
Repair completed.

BR 80012
5.1 Tools, Servicing Aids
–Screwdriver – 0000 890 2300 or equivalent
–Socket, T27x125 – 0812 542 2104 or equivalent
–Torque wrench – 5910 890 0302 or equivalent
–Screwdriver, T27x200 – 5910 890 2415 or equivalent
5.2 Removing the Harness
NPreparations, @ 3.1.
Backplate with extension
NPush the upper sliding adjusters of the harness straps
(1 and 5) through the openings in the backplate.
Backplate without extension
NInsert screwdriver 0000 890 2300 through the
protective screen (see illustration) and use it to pull
the upper sliding adjusters (8) away from the harness
straps (1 and 5) and hold them there.
NPull out the straps (1 and 5).
All versions
NRotate the lower sliding adjusters of the harness
straps (1 and 5) through 90° and push them out
through the openings in the backplate.
NTake out the screws (4).
NRemove the straps (1 and 5).
NTake out the screws (3).
NRemove the waist belt (2).
5 Harness
6
5
1
27 P6x25
(6 Nm /
53 lbf. in.)
4 P5x14
(4 Nm /
35 lbf. in.)
3 P5x14
(4 Nm /
35 lbf. in.)
0000-GXX-6626-A0
5
8
0000-GXX-6643-A0

BR 800 13
5.3 Fitting the Harness
NPosition the waist belt (2) against the backplate.
NInsert and tighten down the screws (3) firmly.
NPosition the harness straps (5) against the backplate.
NInsert and tighten down the screws (4) firmly.
NRotate the lower sliding adjusters of the harness
straps (1 and 5) through 90° and push them in
through the openings in the backplate.
NPush the upper sliding adjusters of the harness straps
(1 and 5) through the openings in the backplate.
5.4 Removing the Backplate Extension
NPreparations, @ 3.1.
NRemove the upper sliding adjusters, @ 5.2.
NTake out the screws (7).
NRemove the backplate (6).
NEngage the upper sliding adjusters, @ 5.3.
5.5 Fitting the Backplate Extension
NPreparations, @ 3.1.
NDisengage the upper sliding adjusters, @ 5.2.
NPlace the backplate (6) in position.
NInsert and tighten down the screws (7) firmly.
NEngage the upper sliding adjusters, @ 5.3.

BR 80014
6.1 Tools, Servicing Aids
–Screwdriver – 0000 890 2300 or equivalent
–Socket, T27x125 – 0812 542 2104 or equivalent
–Torque wrench – 5910 890 0302 or equivalent
–Screwdriver, T27x200 – 5910 890 2415 or equivalent
–Punch-down tool – 5910 890 4000 or equivalent
–Pin punch, 2 mm
–STIHL multipurpose grease – 0781 120 1110
–STIHL gear grease – 0781 417 1315
–STIHL OH 723 press fluid – 0781 957 9000
6.2 Removing the Rewind Starter
NPreparations, @ 3.1.
NTake out the screw (6).
NTake out the screws (7).
NRemove the starter cover (9) with the rope guide (5)
and the starter mechanism (11 - 24).
6.3 Removing the Bearing Shell
NRemove the rewind starter, @ 6.2.
NUnlock and pull off the bearing shell (24).
NRemove the spring (22).
NUnlock and remove the pawls (23)
6.4 Relieving Tension of Rewind Spring
NRemove the bearing shell, @ 6.3.
NPull out the starter grip (4) about 10 cm (4 in).
NHold the rope rotor (13) steady.
NPull out starter rope (3) between the rope rotor (13)
and pulley (10).
NEngage the starter rope (3) in the notch in the rope
rotor (13) and take 4 turns of the rope off the rope
rotor (13) clockwise.
NHold the rope rotor (13) steady.
NPull out the starter grip (2) until the starter rope (3) is
under tension.
NLet go of the rope rotor (13) and guide the starter rope
(3) back into the housing until the rewind spring (11)
is no longer under tension.
6.5 Removing the Spring Housing
NRemove the bearing shell, @ 6.3.
NRelieve tension of rewind spring, @ 6.4.
NRemove the spring clip (21).
NRemove the pawls (20).
NRemove the washer (19).
NPull off the driver (18).
NPull off the spring housing (17).
NRemove the spring (14).
6 Rewind Starter
9
8
10
1
3
4
5
2
13
14 16171819 20 22
21
24
12
11
M5x58x22 7
(6 Nm / 53 lbf. in.)
15
15 23
P5x18 6
(4 Nm /
35 lbf. in.)
0000-GXX-6620-A0

BR 800 15
NRemove the pawls (15).
NRemove the bushing (16).
6.6 Removing the Rewind Spring
WARNING
The rewind spring can pop out and cause serious eye and
hand injuries. Wear safety glasses and work gloves.
NRemove the spring housing, @ 6.5.
NRelieve tension of rewind spring, @ 6.4.
NPull the rope rotor (13) off the starter post.
NHold the spring housing (12) steady.
NUse punch-down tool to unlock the spring housing
(12) at the recesses (arrows) a - b - c in that order.
NRemove the spring housing (12) together with the
rewind spring (11).
NTake the rewind spring (11) out of the spring
housing (12).
6.7 Removing the Starter Rope
NRemove the rewind spring, @ 6.4.
NUnlock and remove the pulley (10).
NPull off the rope guide (5).
NUnwind the starter rope (3) from the rope rotor (13).
NPull the knot (25) out of the rope rotor (13).
NUndo the knot (25).
NUnlock and remove the cap (1).
NPull out the starter rope (3).
NUse punch-down tool 0000 890 2300 to pry out the
guide (4).
6.8 Installing the Starter Rope
NPush the guide (4) into the pulley (5).
NSecure the end of the rope (3) with a simple overhand
knot.
NThread the rope (3) through the starter grip (2), pulley
(5) and rope rotor (13).
NSecure the end of the rope (3) with a simple overhand
knot (25).
NPull the knot (25) back and push it into the recess
(arrow) in the rope rotor.
NPush the cap (1) onto the starter grip (2) so that it
snaps into place.
NPush the rope guide (5) into the starter cover (9).
NFit the starter rope (3) in the pulley (10).
NFit the pulley (10) in the guides (arrows) in the starter
cover (9) so that it snaps into place.
NInstall the rewind spring, @ 6.9.
6.9 Installing the Rewind Spring
WARNING
The rewind spring can pop out and cause serious eye and
hand injuries. Wear safety glasses and work gloves.
12
a
bc
0000-GXX-6628-A0
13
25 1
2
3
5
4
0000-GXX-6630-A0
13
25 1
2
3
3
5
4
0000-GXX-6631-A0
10
3
10
3
0000-GXX-6639-A0

BR 80016
If the spring pops out, refit it in the spring housing as
follows:
NFit anchor loop of rewind spring (11) over the lug (26).
NFit the rewind spring (11) in the housing clockwise,
holding it in place at the same time.
NPush the rewind spring (11) fully into its seat in the
spring housing (12).
Installing the rewind spring
NLubricate the rewind spring (11) in the spring housing
with special lubricant before installing.
NFit the spring housing (12) with rewind spring (11) in
the starter cover (9) so that it locates against the
contour (arrow).
NPress the spring housing (12) fully home so that all
locking tabs snap into place.
NInstall the rope rotor, @ 6.10.
6.10 Installing the Rope Rotor
WARNING
The rewind spring can pop out and cause serious eye and
hand injuries. Wear safety glasses and work gloves.
NInstall the rewind spring, @ 6.9.
NLubricate starter post (27), eyelet (arrow) of rewind
spring (11) and the recess (arrow) in the rope rotor
(13) with multipurpose grease.
NWind the starter rope (3) onto the rotor (13)
counterclockwise so that it is not tensioned when the
rotor (13) is fitted in place.
NPush the rope rotor (13) onto the starter post (27) so
that the eyelet (arrow) of the rewind spring (11)
engages the recess (arrow) in the rotor (13).
NInstall the spring housing, @ 6.11.
6.11 Installing the Spring Housing
NFit the bushing (16) in the spring housing (17).
NLubricate the bushing (16) with multipurpose grease.
NFit the pawls (17).
NFit the spring (14) so that the lobes of the pawls (15)
are outside the spring (14).
NPush the spring (14) into the guides (arrows).
NPush the spring housing (17) onto the starter post.
26
12
11
0000-GXX-6632-A0
12
0000-GXX-6629-A0
27
11
13
0000-GXX-6633-A0
14 16
17
15
15
0000-GXX-6634-A0

BR 800 17
NLubricate eyelet (arrow) of rewind spring (28) with
multipurpose grease.
NPush the driver (18) onto the starter post (27) so that
the eyelet (arrow) of the rewind spring (28) engages
the recess (arrow) in the driver (18).
NFit the washer (19).
NFit the pawls (20).
NFit the spring clip (21) so that its loops (arrows) are
around the pegs (29).
NLubricate the pegs (29), spring clip (21), starter post
groove and washer (19) with multipurpose grease,
making sure the side faces of the pawls (20) remain
grease-free.
NTension the rewind spring, @ 6.12.
6.12 Tensioning the Rewind Spring.
NPull out a short length of starter rope (3) between the
rope rotor (13) and the pulley (10).
NEngage the starter rope (3) in the notch in the rope
rotor (13) and add 4 turns of the rope to the rope rotor
(13) counterclockwise.
NHold the rope rotor (13) steady.
The rewind spring (3) is now pre-tensioned. Rotating the
starter rope (3) and rope rotor (13) causes the rope to
become twisted.
NPull out the twisted rope (3) with the starter grip (2)
and straighten it out.
NKeep the starter rope (3) under tension and allow it to
slowly rewind onto the rope rotor (13).
The starter grip (2) should sit firmly in the rope guide (5).
NIf the starter grip (2) is too loose, rotate the rewind
spring (13) one more turn counterclockwise.
6.13 Installing the Bearing Shell
NFit the pawls (23).
NFit the spring (22) so that the lobes of the pawls (23)
are inside the spring (22).
NPush the spring (22) into the guides (arrows).
NFit bearing shell (24) in the starter cover (9) and
engage it in position.
NInstall the rewind starter, @ 6.14.
18
17
27
28
0000-GXX-6635-A0
20
29
20
19
21
29
0000-GXX-6636-A0
10
313
0000-GXX-6637-A0
30
23
22
24
0000-GXX-6638-A0

BR 80018
6.14 Installing the Rewind Starter
NRemove the starter cover (9) with the rope guide (5)
and the starter mechanism (11 - 24).
NInsert and tighten down the screws (7).
NInsert and tighten down the screw (6).
6.15 Removing the Stop Buffers
NPreparations, @ 3.1.
NRemove the rewind starter, @ 6.2.
NUse punch-down tool 5910 890 4000 to pry the stop
buffers out of the starter cover (9).
6.16 Installing the Stop Buffers
NCoat cones of stop buffers (8) with press fluid.
NPress the stop buffers (8) into the openings in the
starter cover (9).
NInstall the rewind starter, @ 6.14.