Technical Information · issue 36 of 1996
New brushcutters
Model Sound Sound power
IssueTI 36/1996
Full text
Page 1 of 12
Technical Information
36.96
New Model FS 75, 80, 85 Brushcutters - Series 4137
FS 75 FS 80 R FS 80 RB FS 80 R = Loop handle
FS 85 R FS 85 RB FS 85 B = Barrier bar
These new brushcutters are further developments This powerhead has a displacement of 25.4 cm3
of models FS 72, 74 and 76. (1.55 cu.in) and a power output of 0.9 kW
The engine installed in the three models is exactly (1.2 bhp).
the same as that installed in model BG 75 blower
and the HS 75, 80, 85 hedge trimmers. The new units can be used for the same range of
applications as models FS 72, 74, 76.
)Technical Information 36.96 - Page 2
&RQWHQWV
1. Technical Description
2. Specifications
3. Cutting Tools
4. Special Accessories for User
5. Service Accessories
6. Repairs
7. Replacement Parts
Only the differences between models FS 75, 80,
85 and models FS 72, 74, 76 are described in
the following. For further information see
TI 12.92 =models FS 72, 74 and 76=.
1.=Technical Description
&UDQNVKDIW
• Durable machined design
&\OLQGHU
• Four port technology (better mixture control, fo
cleaner combustion, lower emissions).
• Larger cooling area
&DUEXUHWRU
• Fixed high speed jet with one idle mixture
adjusting screw (L; see table 2.1.2)
Air filter
• Improved filter material
• Larger effective filter surface area
Exhaust muffler
• Two-chamber muffler
• Spark arresting screen easier to remove and
install
Rewind starter
• With ElastoStart starter grip
&RQWUROV
• 1HZ control handle, functions as on
STIHL FS 72, 74, 76, 86, 88, 106, 108.
• Control handle with two short circuit wires (1) or STOP START
with one short circuit wire (2) on ignition module.
Throttle cable performs functions of short circuit
wires in version with one wire on the ignition
module.
• Fewer component parts
&OXWFK
• Three clutch shoes without linings
392TI002 KN
1 2
)Technical Information 36.96 - Page 3
Drive shaft
• FS 75, 80=flexible shaft,
FS 85=rigid shaft,
supported in a protective tube on all models.
3 4
Cutting tool mounting
• FS 75=output shaft (4), as STIHL FS 72
with M12 right-hand thread;
FS 80, 85=output shaft (3), as STIHL
392TI003 KN
FS 74, 76, 86, 88, 106, 108 with M10 x 1
left-hand thread.
2.=======Specifications
2.1======Powerhead
2.1.1=Engine
Displacement: 25.4 cm3 (1.55 cu.in)
Bore: 34 mm (1.34 in)
Stroke: 28 mm (1.10 in)
Engine power to ISO 8893: 0.9 kW (1.2 bhp)
Engine speeds: see 2.1.2
Rewind starter: Single pawl system; ElastoStart grip
Starter rope: see 4.
Clutch diameter: 66.5 mm (2.62 in)
Clutch engages at: 3,700 rpm
Model Sound Sound power
pressure level Lweq
level Lpeq to ISO 108841)
to ISO 7917 1)
dB (A) dB (A)
FS 75 Cutting hd. 97
FS 80 Cutting hd. 98
FS 80 Metal tool 91
FS 85 Cutting hd. 97
FS 85 Metal tool 92
1)
Data includes idling and full throttle/no load
with the same duration of exposure
)Technical Information 36.96 - Page 4
2.1.2=Fuel System
Carburetor: All position diaphragm carburetor with integral fuel pump
B C
366TI004 KN
C1Q-S28A carburetor
B = Idle fixed jet, 0.32 mm diam.
C = Valve jet with integral
fixed jet, 0.41 mm diam.
Settings=====================================================C1Q-S28A
=DPD
Low speed screw / (standard setting) Open 1 turn
Idle speed 2800 rpm
High speed screw + (standard setting) QRQH
Cut-off speed (without cutting tool) 9500 to 11500 rpm
Max. output shaft speed FS 75 8500 rpm
(rated) FS 80, 85* 7500 rpm
* with gear ratio of 1:1.4
Fuel capacity: 0.44 l (0.9 US pt)
2.1.3=Ignition System
Ignition timing: 1.55 - 2.25 mm (0.060 - 0.090 in) B.T.D.C. at 8000 rpm
Length of ignition lead: 160 mm (6.3 in)
Spark plug (suppressed): Bosch WSR 6F, NGK BPMR 7 A
or Champion RCJ 6Y
2.2=======Gearhead =FS 80, 85
Gear ratio: Start of production 1:1.33, later 1:1.4
2.3=======Weight
FS 75 FS 80 R FS 80 FS 85 R FS 85
without cutting tool and deflector 4.0 kg 4.8 kg 5.0 kg 4.9 kg 5.1 kg
(8.8 lb) (10.6 lb) (11.0 lb) (10.8 lb) (11.2 lb)
)Technical Information 36.96 - Page 5
3.=====Cutting Tools==========================================1=======================2
The following cutting tools are approved for use
681FK003
with these brushcutters:
1=pqfei=pupercut 10-1 cutting head 1)
QMMQ=TNM=ONNM========================================3=======================4
===== 2=pqfei=pupercut=OMJO=cutting=he~d=OF
4002 710 2162
3=pqfei=^utocut 11-2 cutting head 1)
4004 710 2105
===== 4=pqfei=^utocut=ORJO=cutting=he~d=OF==================5========================6
4002 710 2108
===== 5=pqfei=^utocut=PMJO=cutting=he~d=OF
4002 710 2107
===== 6=pqfei=molym~tic=PMJO=cutting=he~d=OF
4002 710 2120
7=======================8
7=pqfei=molycut 10-3 cutting head 1)
4004 710 2130
===== 8=pqfei=molycut=OMJP=cutting=he~d=OF
4002 710 2130
9=`utting blade 230-4 3)
QMMN=TNP=PUMN=======================================9========================10
10=`utting blade 230-8 3)
4001 713 3803
11=_rush knife 250-3 3)
4112 713 4100
12=`ircular saw blade 200 (scratcher tooth) 4)
11======================12
4112 713 4201
13=`ircular saw blade 200 (chisel tooth) 4)
4112 713 4203
1)
FS 75
2)
FS 80, 85: all versions 13
3)
FS 80, 85: use only with barrier bar or
bike handle
4)
FS 80, 85: only for bike handle version
4.===Special Accessories for User
Part Name Part No. Application, Remarks
Transport guard for
metal cutting tools 4119 790 3906 Cutting blade 230-4, 230-8, brush knife 250-3
4119 790 3901 Circular saw blade 200 (scratcher/chisel tooth)
ElastoStart grip 0000 190 3400 Rewind starter (grip with rope)
ElastoStart grip 0000 195 8200 Rewind starter
STIHL multipurpose grease Drive shaft
- Tube 80 g (3 oz) 0781 120 1109
STIHL gear lubricant Gearhead
- Tube 80 g (3 oz) 0781 120 1117
)Technical Information 36.96 - Page 6
4.1===Nylon Line for Cutting Heads
Line Application
diam. / color
.080 in/ green Autocut 11-2
.095 in/ orange Supercut 10-1, Supercut 20-2, Autocut 25-2, Autocut 30-2,
Polymatic 30-2, Polycut 10-3, Polycut 20-3
.105 in/ red Polycut 10-3, Polycut 20-3
4.2===Sharpening Aids for Metal Cutting Tools
Part Name Part No. Application
Saw set 4020 893 5000 Circular saw blade 200 (chisel tooth)
5.====Service Accessories
5.1===Special Servicing Tools
5.1.1=New for Models FS 75, 80, 85
2 3
4 5
sio 392TI004 KN
392TI005 KN
Item Part Name Part No. Application Rem.
1 Installing tool; 5910 890 2202 Installing crankshaft
including items 2 and 3
2 Sleeve 5910 893 1700
3 Spindle 5910 893 8501
4 Radial seal puller; 5910 890 4400 Oil seals 1)
including item 5
5 Spindle 5910 890 8400
1) Original spindle of puller 0000 890 4400 can be replaced by spindle 5910 890 8400, which is
20 mm (0.80 in) longer. The original puller is then exactly the same as puller 5910 890 4400.
)Technical Information 36.96 - Page 7
5.1.2===Existing Special Servicing Tools
Use special servicing tools for FS 72, 74, 76 for all other operations not mentioned below.
Part Name Part No. Application Rem.
Press sleeve 1115 893 4600 Installing the oil seal (starter side)
Assembly sleeve 4112 893 2400 Protecting the oil seal (starter side)
Press sleeve 4112 893 2401 Installing the oil seal
(clutch side)
Installing tool 4126 893 4900 Removing rubber AV element and
AV sleeve 1)
Installing tool 5910 890 2208 Fitting hookless snap rings
in piston 2)
Service tool ZS 5910 007 2220 Removing the crankshaft
including
- Installing tool 5910 890 2220
- Sleeve (1x; 30 mm) 5910 893 1701 4)
- Sleeve (2x; 35 mm) 5910 893 1702 4)
1) Drive tube diameter: 25.4 mm (1")
2) See modification 5.1.2.1
3)
4)
See modification 5.1.2.2
Part must be acquired for new models
5.1.2.1=Modification of
installing tool 5910 890 2208
The latest factory-supplied version of installing
tool 5910 890 2208 has been modified for use
in models FS 75, 80, 85. 6
Existing installing tools can be modified
as shown in the drawing on the right. 35,5
(1,398")
6
392TI006 KN
17,3
(0.681")
)Technical Information 36.96 - Page 8
5.1.2.2=Modification of
installing tool 5910 890 2220
In future, the factory-supplied installing tool
5910 890 2208 will come with six additional
5.5 mm (7/32") holes for use on models FS 75,
80, 85.
6
15 11
Existing installing tools which do not have these ho- 2
4
les can be modified with the aid of the scale
template on the last page of this TI. 14
87 5
To mark the new holes, copy the template, cut it
12
out and place it on the underside of the flange.
Stamp the numbers 14 and 15 next to the holes
on the top side of the flange.
14
14
15
10
Apply new notches to the periphery of the flange
and stamp the numbers 14 and 15 next to them. 15
9
14 /6
31
The illustration on the right shows the top side 3
392TI007 KN
15
of the new version of the flange. 1
5.2=====Servicing Aids
Part Name Part No. Application
Carburetor parts kit 4227 007 1060 Zama C1Q-S28A
6.======Repairs
If the unit is started up in the course of repairs
or maintenance work, always observe all local
regulations and the safety precautions outlined
in the owner¶s manual.
)Technical Information 36.96 - Page
6.1===Setting Data for Zama C1Q-S28A Carburetor
This carburetor does not have a high speed
adjusting screw (H screw).
Emissions at idle speed and part-load revs are
reduced by using a lean idle mixture.
Standard setting
L = lpen 1=turn
Carefully screw home low speed screw clockwise
until it is against its seat. Then rotate it one turn
counterclockwise.
• Mount the cutting tool -
==If nylon line cutting head is fitted
Check length of line. (DFK line must extend
as far as limiting blade on deflector.
• Check air filter and clean if necessary
• Start the engine and warm it up L
Set idle speed to 2,800 rpm with idle speed
screw (/$).
If running problems occur at this standard
setting =e.g. engine stalls while idling, poor====================i^
acceleration=, carry out the following
392TI009 KN
DGMXVWPHQWV
Poor acceleration or engine stalls
a) Check standard setting EL = 1F
b) Rotate low speed screw (/) one eight turn
counterclockwise
c) Set idle speed to 2,800 rpm with idle speed
screw (/$)
If necessary, repeat adjustments b and c.
Engine stalls during transition from full load to
idle speed or runs erratically at idle speed
a) Check standard setting EL = 1F
b) Rotate low speed screw (/) one eighth turn
clockwise
c) Set idle speed to 2,800 rpm with idle speed
screw (/$)
If necessary, repeat adjustments b and c.
)Technical Information 36.96 - Page 10
Cutting tool rotates at idle speed
a) Set idle speed to 2,800 rpm with idle speed
screw (/$)
b) Turn idle speed screw (/$) counterclockwise
until cutting tool stops rotating - then turn it
another one half turn in the same direction.
392TI009 KN
6.2=====Testing Data
6.2.1===Leakage Test
6.2.1.1=Engine
- under pressure: 0.5 bar (7.25 psi)
- under vacuum: 0.5 bar (7.25 psi)
6.2.1.2=Carburetor
- Inlet needle testing: 0.8 bar (11.6 psi)
6.3=====Tightening Torques
Tightening torques are listed in the service
manual for the STIHL FS 75, 80, 85; FC 75
and HL 75.
)Technical Information 36.96 - Page 11
6.4===Service Note
=============================================Code===Type of Repair========================HL 75
A service manual is available for the
STIHL FS 75, 80, 85.
This service manual contains no
chapters on "Servicing the Carburetor", 1 Crankcase, Short Block 2.1
"Troubleshooting" or standard repairs.
These procedures are described in 2 Crankcase and/or Bearings 2.2
separate manuals. 3 Crankcase Gasket, Sealing 2.0
6.5===Repair Times==============================Q===`rankshaft Seals 0.7
The specified repair times assume that 5 Cylinder and/or Piston 0.8
the work is performed by trained
6 Ignition 0.5
personnel in a properly equipped
service workshop. 7 Fuel Hose, Fuel Supply 0.5
The repair times are given in tenths of 8 Replace Gear Box Assy 0.5
an hour (0.1 = 6 minutes).
9 Carburetor 0.7
Note:=qhe brushcutter repair times on 10 Fan Housing, Clutch Housing 0.8
the right can be used to update the
STIHL repair times table manual. 11 Front Handle, Throttle 0.6
12
Recoil Starter 0.5
13 Clutch 0.5
7.====Replacement Parts========================NQ===arive Tube, Drive Shaft 0.5
A separate parts list is available for the 15 Muffler 0.4
new units. 16 Air Filter, Filter Cover 0.3
17 Stop Switch 0.4
18 Fuel Tank 0.4
19 Replace Arbor Gears 0.8
20 All Other Repairs & Misc. Repairs 0.5
✂
Note:=^ll repairs include diagnostic time.
Andreas Stihl D1/MTK-na
© 1996 Andreas Stihl Technical Documentation 5872
)Technical Information 36.96 - Page 12
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Extracted from the manufacturer's 2012 service catalogue. Most of these PDFs embed fonts with a shifted character map, so the text above was recovered rather than copied — read it as a faithful but imperfect transcription, and treat the page image above each block as the authority where the two disagree — the figures exist only there, because they are vector drawings that text extraction cannot keep.