STIH)
STIHL Series 4137 Components
BG, HS 2004-07
1 BG 75, HS 75, HS 80, HS 85
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© ANDREAS STIHL AG & Co. KG, 2004
Contents
1. Introduction 2
2. Safety Precautions 3
3. Specifications 4
3.1 Fuel System 4
3.2 Gearbox 4
3.3 Tightening Torques 5
4. Troubleshooting 8
4.1 Clutch/Blade Lock 8
4.2 Rewind Starter 9
4.3 Fuel System 10
4.4 Engine 12
5. Clutch/Blade Lock 13
5.1 Clutch 13
5.2 Clutch Drum 14
5.3 Blade Lock 15
5.3.1 Checking Operation 15
5.3.2 Brake Band 15
5.3.3 Adjusting 17
6. Engine 17
6.1 Removing and Installing
(HS 75, 80, 85) 17
6.2 Removing and Installing
(BG 75) 19
6.3 Muffler/Spark Arresting
Screen (HS 75, 80, 85) 20
6.4 Muffler/Spark Arresting
Screen (BG 75) 21
7. Rewind Starter 21
7.1 General 21
7.2 Removing and Installing
(HS 75, 80, 85) 22
7.3 Removing and
Installing (BG 75) 22
7.4 Rope Rotor/
Rewind Spring 22
7.5 Starter Rope 24
7.6 Starter Grip 25
7.7 Tensioning 25
7.8 Carrier/Pawl 26
8. AV System 27
8.1 Repair (HS 75, 80) 27
8.2 Repair (HS 85) 28
9. Throttle Control 30
9.1 Control Handle (HS 75) 30
9.1.1 Throttle Trigger/
Interlock Lever 30
9.1.2 Throttle Cable 31
9.1.3 Blade Lock Lever/
Brake Cable 31
9.1.4 Short Circuit Wires 31
9.1.5 Contact Spring 32
9.2 Control Handle (HS 80) 32
9.2.1 Throttle Trigger/
Interlock Lever 32
9.2.2 Throttle Cable /
Brake Cable 34
9.2.3 Short Circuit Wires 34
9.2.4 Blocking Lever 34
9.2.5 Contact Spring 35
9.3 Control Handle (HS 85) 35
9.3.1 Throttle Trigger/
Interlock Lever 35
9.3.2 Throttle Cable/
Short Circuit Wires 36
9.3.3 Handlebar/Blade Lock
Lever/Brake Cable 36
9.3.4 Contact/Detent Springs 37
9.4 Adjusting the Throttle
Cable (HS 75, 80, 85) 38
9.5 Control Handle (BG 75)38
9.5.1 Throttle Trigger/
Throttle Rod 38
9.5.2 Contact Spring 39
10. Fuel System 39
10.1 Air Filter 39
10.1.1 Choke Shutter 40
10.2 Carburetor 40
10.2.1 Leakage Test 40
10.2.2 Removing and
Installing 41
10.2.3 Manual Fuel Pump
with Oval End Cover 43
10.2.4 Manual Fuel Pump
with Square End Cover 44
10.2.5 Metering Diaphragm 44
10.2.6 Inlet Needle 45
10.2.7 Pump Diaphragm/
Fuel Strainer 45
10.2.8 Control Valve 46
10.2.9 Adjusting 46
10.3 Spacer Flange 47
10.4 Fuel Tank/Hoses/Pickup
Body (HS 75, 80, 85) 48
10.5 Fuel Tank/Hoses/
Pickup Body (BG 75) 50
10.6 Tank Vent 51
11. Cutting Attachment 52
11.1 Cutting Blades
(HS 75, 80) 52
11.2 Cutting Blades
(HS 85) 55
11.3 Spur Gear
(HS 75, 80, 85) 59
11.4 Gear Housing
(HS 75, 80, 85) 60
11.5 Handle (HS 85) 60
12. Blower and Vacuum
Attachment 60
12.1 Intake Screen 60
12.2 Fanwheel 61
12.3 Blowing Attachment 62
12.4 Vacuum Attachment
(special accessory) 62
12.5 Assist Handle
(special accessory) 62
13. Special Servicing
Tools 64
14. Servicing Aids 65
2 BG 75, HS 75, HS 80, HS 85
This service manual contains
detailed descriptions of all typical
repair and servicing procedures for
models BG 75, HS 75, HS 80 and
HS 85, which are based on the
series 4137 powerhead.
You will find detailed descriptions of
procedures for servicing and
repairing engine components in the
service manual for the “Series 4137
Powerhead“.
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 chapter on
"Troubleshooting" in this manual
and the "STIHL Service Training
System" for all assemblies.
Refer to the "Technical Information"
bulletins for engineering changes
which have been introduced since
publication of this service manual.
Technical information bulletins
supplement the service manual and
parts list until revised editions are
issued.
The special servicing tools
mentioned in the descriptions are
listed in the chapter "Special
Servicing Tools" of this manual.
Use the part numbers to identify the
tools in the "STIHL Special Tools”
manual. 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
aDirection of movement
b 4.2 Reference to another
chapter, i.e. chapter 4.2
in this example.
Service manuals and technical
information bulletins are intended
exclusively for the use of properly
equipped repair shops. They must
not be passed to third parties.
Servicing and repairs are made
considerably easier if the machine
is mounted on assembly stand (2)
5910 893 3100 with the aid of
clamping plate (1) 5910 890 2100
after removing the shroud, starter
cover and fuel tank.
VA 366RA001
2
1
The powerhead can then be
swivelled to the best position for the
ongoing repair.
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.
1. Introduction
3 BG 75, HS 75, HS 80, HS 85
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 instruction 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 bring any fire, flame, spark or
other source of heat near the fuel.
All work with fuel must be performed
outdoors only. Spilled fuel must be
wiped away immediately.
2. Safety Precautions
4 BG 75, HS 75, HS 80, HS 85
3. Specifications
3.1 Fuel System Carburetor: Diaphragm carburetor
Carburetor leakage test at gauge
pressure: 80 kPa (0.8 bar)
Fuel mixture: Regular brand-name gasoline and
STIHL 50:1 two-stroke engine oil; see
instruction manual for further details
Octane number: min. 90 RON
Operation of tank vent:
- at gauge pressure: 50 kPa (0.5 bar)
- under vacuum: 20 kPa (0.2 bar)
3.2 Gearbox Type: Straight-toothed spur gears
(single stage)
Gear ratio: 1:5.6 (+X 36 360 021)
1:7.1 (older machines)
Bearings: Deep-groove ball bearings
Lubrication: STIHL gear lubricant for hedge
trimmers
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Stihl HS 75 , 80 , 85 & BG 75 Workshop Service Repair Manual
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Description
This manual is suitable for both first-time owners and amateur enthusiasts, as well as professional technicians. It is designed in an easy-to-read format and provides comprehensive information necessary to carry out procedures accurately.
- Models Covered:
- Stihl HS 75
- Stihl HS 80
- Stihl HS 85
- Stihl BG 75
It is recommended to keep this service manual accessible and refer to it regularly. Regular and preventive maintenance can help save time and money by preventing premature failure and unnecessary repairs.
- Manual Contents:
- Introduction
- Specifications
- Clutch, Chain Drive, Chain Brake And Chain Tensioner
- Engine
- Ignition System
- Rewind Starter
- AV Handle System
- Master Control / Handle System
- Chain Lubrication
- Fuel System
- Special Servicing Tools And Aids
File Format: PDF
Compatible with all versions of Windows & Mac
Language: English
Requirements: Adobe Reader
