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Technical Information · issue 3 of 2002

New brushcutter model FS 85 RX

IssueTI 3/2002

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TI 3/2002 page 1
Technical Information

                                                                               03.2002
New brushcutter model STIHL FS 85 RX – Series 4137

Contents
1.   Technical description
2.   Specifications

3.   Tools

4.   Accessories for the user
5.   Service accessories
6.   Repairs

7.   Spare parts

                                         The new brushcutter model STIHL FS 85 RX is
                                         fitted with a lightweight aluminium drive shaft as a
                                         standard feature. This makes the machine lighter
                                         than the FS 85 models with steel shaft and also
                                         makes it particularly suitable for professional lawn
                                         care maintenance.

                                         The FS 85 RX brushcutter should only be used with
                                         mowing (grass cutting) heads, see 3. "Tools".
                                         STIHL no longer recommends the use of metal

                                         blades or gear box attachment accesories on any
                                         FS 85 machine (bike or loop handle version) that

                                         has an inner aluminum drive shaft. In these cases a
                                         solid steel drive shaft (part no. 4137 711 3200) and
                                         matching liner (4137 711 7300) can be installed by

                                         the dealer.

TI_03_2002_01_01_01.fm                                                          english / USA
)m~ge 2                                                                                Technical Information 03.2002

1.      Technical description
All parts except for the shaft and liner are identical
with those of the standard FS 85 model with a steel
shaft.
Drive shaft

             8 mm (0.315")

                                                       393TI024 BL

.     Lightweight hollow alluminium inner drive shaft,
      approx. 0.5 lbs (0.2 kg) lighter than a steel shaft

2.      Specifications
2.1     Engine

2.1.1 Powerhead
Single-cylinder two-stroke engine
Displacement:                                 1.55 cu.in (25.4 cc)

Bore:                                         1.34 in (34 mm)

Stroke:                                       1.10 in (28 mm)
Engine power to ISO 8893:                     1.3 HP (0.95 kW)
                                              at 8,500 rpm
Speeds:                                       See 2.1.2

Rewind starter:                               Single pawl system
Starter rope:                                 0.118 in (3 mm) diameter,

                                              33.5 in (850 mm) long
Clutch:
- Engages at:                                 3,700 rpm

2.1.2 Fuel system
Carburetor: All-position diaphragm carburetor with integral fuel pump

High speed adjusting screw H (standard setting)
- Without limiter cap (when performing service repairs):                  1.5 turns open
- With limiter cap (for user):                                            3/4 turn counter-clockwise
Idle speed screw L (standard setting):                                    1 turn open
Idle speed adjusting screw LA:                                            As required, cutting tool must not turn at
                                                                          idle
Idle speed:                                                               2,500 to 3,100 rpm
Governor speed range without cutting tool
(electronic speed governor):                                              9,700 to 11,300 rpm

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Technical Information 03.2002                                                                         Page 3

Fuel tank capacity:                0.9 US pt (0.44 L)
Fuel mix:                          Mid-grade brand name gasoline (89 octane) and brand name air cooled
                                   two-stroke engine oil
Mix ratio:                         1:50 for STIHL two-stroke engine oil

2.1.3 Ignition system
Ignition module:                   With integrated electronic
                                   speed governor
Spark plug (suppressed):           Bosch WSR 6F,
                                   NGK BPMR 7 A or
                                   Champion RCJ 6Y

2.2    Weight
Without cutting tool
and deflector:                     10.6 lbs (4.8 kg)

3.     Tools
The following cutting tools are approved:
1     STIHL SuperCut 20-2        4002 710 2184
2     STIHL AutoCut 21-2         4002 710 2192
3     STIHL AutoCut 25-2         4002 710 2191
                                                                                               2

4     STIHL TrimCut 30-2         4002 710 2193                          1
5     STIHL PolyCut 20-3         4002 710 2189
6     STIHL grass trimmer        4001 713 2100

The use of metal cutting blades is not permitted.

                                                                        3                      4

                                                                                                          393TI022 KN

                                                                        5                      6

4.     Accessories for the user

4.1    General

Part name                           Part No.              Application
ElastoStart                         0000 190 3405         Rewind starter (starter handle with rope)
Starter rope                        0000 195 8203         Rewind starter, also for ElastoStart

STIHL gear lubricant for                                  Gearhead
brushcutters
- 3 oz (80 g) tube                  0781 120 1117
- 8 oz (225 g) tube                 0781 120 1118

TI_03_2002_01_01_01.fm
)m~ge 4                                                                      Technical Information 03.2002

4.2   Nylon line for mowing heads

Line diameter / color                Use
0.095 in / orange                    SuperCut 20-2, AutoCut 21-2, AutoCut 25-2, TrimCut 30-2, PolyCut 20-3,
                                     grass trimmer
0.105 in / red                       PolyCut 20-3, fixed line head

5.    Service accessories

5.1   Special servicing tools

The special servicing tools are listed in the service manual for STIHL FS 75, 80, 85, FC 75, HL 75.

5.2   Servicing aids

Part name                            Part No.             Application
Set of carburetor parts              4227 007 1060        Carburetor Zama C1Q-S28, -S41, -S45, -S56, -

                                                          S60, -S63
Lubricating grease                   0781 120 1111        Oil seals
- 8 oz (225 g) tube
Dirko sealant                        0783 830 2120
                                                          Seal between engine pan and cylinder
Electrical repair kit                5910 007 1050        Electrical system
Standard commercial                                       Cleaning the crankshaft stub
solvent-based degreasant

containing no chlorinated or
hydrogenated hydrocarbons

6.    Repairs

Specific national safety regulations and the safety       This service manual does not contain any chapters
instructions in the User Manual must be observed          on "Repairing the carburetor" and
when starting the machine.                                "Troubleshooting", nor does it describe standard

                                                          repairs. These service notes can be found in the
6.1   Tightening torques                                  manuals "Carburetor", "Standard repairs and

The tightening torques for the FS 85 RX are listed in     troubleshooting".
the service manual for STIHL FS 75, 80, 85, FC 75,
HL 75.                                                    6.3   Repair times

                                                          The repair times are the same as for the
6.2   Service note                                        STIHL FS 85.
The service manual for STIHL FS 75, 80, 85, FC 75,

HL 75 is available for servicing and repair of the
STIHL FS 85 RX.                                           7.    Spare parts
                                                          The spare parts for the FS 85 RX are integrated into
                                                          the spare parts list for the FS 85.

© 2002 Andreas Stihl AG & Co.                             Technical Documentation
  Waiblingen                                              D1/MTK-na                                      7481

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