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Technical Information · issue 42 of 1997

New Brushcutters/Clearing Saws

IssueTI 42/1997

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TI 42/1997 page 1
Technical Information

                                                                                                 42.97 

New Brushcutters/Clearing Saws========STIHL FS 120, 200, 350========-  Series 4134
                                      STIHL FS 400, 450=============-  Series 4128

FS 120 R                 FS 200                        FS 350                    FS 450 K

The new semi-professional FS 120 and 200

                                                       Numerous improvements have been incorporated
brushcutters/clearing saws are successors to           in the new brushcutters/clearing saws to provide
models STIHL FS 88 and 108. The engine                 greater operator comfort, user friendliness and

installed in the FS 120 is a new development           economy:
with a power output of 1.3kW/1.8bhp (FS 88:
0.9kW/1.2bhp), while that of the FS 200 produces       • Optimized antivibration system
1.6kW/2.2bhp (FS 108: 1.1kW/1.5bhp). This              • Soft control handles with
significant increase in power over the previous          non-slip grip surface
models provides benefits in all mowing and
trimming operations.
                                                       • STIHL easy start system
                                                       • Electronic engine speed limiter
The new professional FS 350, 400 and 450===============• New comfortable full harness (option)
brushcutters/clearing saws replace models FS
160, 180, 220 and 280. The engine installed in the     A new longlife air filter system, together with a
model FS 350 is basically the same as that used in     compensator carburetor- a world first in brushcut-
models FS 120 and 200.                                 ters, extendsfilter life and efficiency.

The recommended applications of these models
are the same as those of the models they replace.
)42.97 - 2

&RQWHQWV

1.    Technical Description
2.    Specifications
3.    Cutting Tools
4.    Special Accessories for Users
5.    Service Accessories
6.    Repairs
7.    Spare Parts

The following descriptions spotlight the 
differences over the previous models 
FS 88, 108, 160, 180, 220, 280.

1.====Technical Description

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• Newly developed STIHL single cylinder
  two-stroke engine.

&\OLQGHU
• Four port technology (better mixture control,                   fo
  clean combustion, lower emissions).
• Decompression valve (on FS 350, 400, 450).
&DUEXUHWRU
• With one adjusting screw.

• With compensator; increases filter efficiency
  by compensating for changes in pressure in
  the carburetor as filter becomes loaded with dirt.

Air filter

• New longlife air filter system with

                                                                                                               250TI007 KN
  paper filter element.
• Larger effective filter surface area.

                                                           Air filter system, carb with stub for compensator
Exhaust muffler
• Spark arresting screen maintained without

  tools (on FS 120, 200, 350).

Easy start system
• Decompression valve (on FS 350, 400, 450).

• ElastoStart starter grip
• Manual fuel primer

&RQWUROV
• New multi-function handle with soft, non-slip
     grip surface.
• Special bike handle for mowing applications
     (FS 350, 400, 450).
• Special bike handle for sawing applications
  (FS 350, 400, 450).
• Bike handle can be adjusted without tools and
  swings parallel to drive shaft for easy transportation
                                                                                                                     250TI008 KN

  (FS 350, 400, 450).
)=====================================================================================================42.97 - 3

&OXWFK
• Two large diameter clutch shoes without linings.
Shaft in drive tube
• Rigid shaft supported in a full length liner.
Four-point AV system =FS 350, 400, 450
• Newly developed four-point AV system reduces vibrations by up to 60%.
Fuel system
• Transparent tank for easy identification of fuel level.

2.====Specifications

2.1===Powerhead

2.1.1=Engine
                                  FS 120              FS 200

                                                      FS 350           FS 400             FS 450

Displacement:                     30.8 cc (1.88 ci) 36.3 cc (2.21 ci) 40.2 cc (2.45 ci)   44.3 cc (2.70 ci)
Bore:
Stroke:
                                  35 mm (1.37 in)
                                  32 mm (1.26 in)
                                                     38 mm (1.49 in)
                                                     32 mm (1.26 in)
                                                                        40 mm (1.57 in)
                                                                        32 mm (1.26 in)
                                                                                          42 mm (1.65 in)
                                                                                          32 mm (1.26 in)
Engine power to ISO 8893:         1.3 kW (1.8 bhp) 1.6 kW (2.2 bhp) 1.9 kW (2.6 bhp)      2.1 kW (2.8 bhp)
Engine speeds:                    see 2.1.2          see 2.1.2          see 2.1.2         see 2.1.2
Rewind starter:                                Single pawl system; ElastoStart grip
Starter rope:                     see 4.             see 4.             see 4.            see 4.

Clutch:
- Clutch engages at:              4300 rpm            4300 rpm         4300 rpm           4300 rpm
)42.97 - 4

2.1.2=Fuel system

Carburetor: All position diaphragm carburetor with integral fuel pump

Carburetor adjusments======================================1 adjusting screw
Zama=======================================================Model C1Q-S34A/C1Q-S36B
Low speed screw / (standard setting)                       1RQH
Idle speed                                                 2,800 rpm
High speed screw + (standard setting)                      1RQH
Cut-off speed range without cutting tool                   11,700 to 13,300 rpm
(electronic speed limiter)

Max. speed (rated) of output shaft

(cutting tool mounting)

FS 120, 200                   with bike handle             18,930 rpm
FS 120, 200                   with loop handle             10,000 rpm

FS 350, 400, 450                                           10,000 rpm

Fuel tank capacity:
FS 120, 200, 350                     0.64 l (1.35 US pt)
FS 400, 450                          0.68 l (1.43 US pt)

2.1.3=Ignition system

Ignition module:                     with integral electronic speed limiter

Length of ignition lead

(FS 400, 450):                       305 mm (12 in)
Spark plug (suppressed):             Bosch WSR 6F, NGK BPMR 7 A or Champion RCJ 6Y

2.2===Gearhead

Gear ratio:
FS 120, 200 (with bike handle):      1.4
FS 120, 200 (with loop handle):      1.235

FS 350, 400, 450                     1.235

2.3===Weights

                                               FS 120 R      FS 120       FS 350    FS 400    FS 400 K
                                               FS 200 R      FS 200                 FS 450    FS 450 K

without cutting tool and deflector             5.8 kg        6.0 kg       7.0 kg    7.9 kg    8.0 kg
                                               12.8 lb       13.2 lb      15.4 lb   17.4 lb   17.6 lb
)=============================================================================================42.97 - 5

3.======Cutting Tools

The following cutting tools are approved:

FS 120, 200

  1=pqfei=pupercut OMJO================================1========================2
    4002 710 2162
  3=pqfei=^utocut 25-2

                                                                                                 681FK001
                                                                     681FK003
    4002 710 2108
  4=pqfei=^utocut 30-2
    4002 710 2107
  7=pqfei=molymatic PMJO========================================================4, 5, 6
                                                       3

    4002 710 2120

  9=pqfei=molycut 20-3
    4002 710 2130
11=`utting blade 230-4 1)

    4001 713 3801
13=`utting blade 230-8 1)
    4001 713 3803
                                                       7, 8

15=_rush knife 250-3 1)
    4112 713 4100
17=`ircular saw blade 200 (scratcher tooth) 2)
    4112 713 4201
20=`ircular saw blade 200 (chisel tooth) 2)
    4112 713 4203
                                                                                11, 12
                                                       10
1)
      Not for loop handle units without b~rrier bar
2)

      Only approved for bike handle units

FS 350, 400, 450

                                                       13, 14===================15, 16
  2=====pqfei=pupercut 40-2

        4003 710 2140
  5=====pqfei=^utocut 40-2
        4003 710 2125
  6=====pqfei=^utocut 40-4 3)

        QMMR=TNM=ONMM==================================17, 18, 19===============20, 21, 22
  8=====pqfei=molymatic 40-2

        4003 710 2100
10======pqfei=molycut 40-3
        4111 710 2100
12======`utting blade 230-4

        4000 713 3801
14======`utting blade 255-8
        4000 713 3802

16======_rush knife 300-3
        4119 713 4100
18======`ircular saw blade 200 (scratcher tooth)
        4000 713 4200
19======`ircular saw blade 225 (scratcher tooth) 4)
        4000 713 4205
21======`ircular saw blade 200 (chisel tooth)
        4119 713 4200
22======`ircular saw blade 225 (chisel tooth) 4)
        4110 713 4204
3)
      For FS 450 only
4)
      For FS 400, 450 only
)42.97 - 6

4.====Special Accessories for Users

Part Name                   Part No.           Application, Remarks

Transport guard for         4116 790 3900      For all metal cutting tools
metal cutting tools
                            4119 790 3906      Cutting blade 230-4, 255-8, circular saw blade 225
                                               (scratcher and chisel tooth)
                            4119 790 3901      Circular saw blade 200 and 225 (scratcher and chisel tooth)

Intake air                  4128 007 1001      For operation in extremely cold conditions
preheating kit
(FS 400, 450)

ElastoStart grip            0000 190 3400      Rewind starter (grip with rope)
ElastoStart rope            0000 195 8200      Rewind starter

STIHL gear lubricant                           Drive shaft in drive tube
- 80 g/3 oz tube            0781 120 1109
- 225 g/8 oz tube           0781 120 1110

STIHL gear lubricant                           Gear box
- 80 g/3 oz tube            0781 120 1117
- 225 g/8 oz tube           0781 120 1118
4.1===Nylon line for cutting heads

Line diameter         For use with
/ color

0.095"

orange                Supercut 20-2, Supercut 40-2, Autocut 25-2, Autocut 30-2, Autocut 40-4, Polymatic 30-2,
                      Polymatic 40-2, Polycut 20-3, Polycut 40-3

0.105"
red                   Autocut 40-2, Polycut 20-3, Polycut 40-3

4.2===Sharpening aids for metal cutting tools

Part Name                   Part No.           Application

Saw set                     4020 893 5000      Circular saw blade 200 and 225 (chisel tooth)

Sharpening template         4020 890 5500      Brush knife
)==============================================================================================================42.97 - 7

5.====Service Accessories

5.1===Special Servicing Tools

Special servicing tools are listed in the service
manual for models FS 120, 200, 350, 400, 450.

5.1.1=Modifying 
      installing tool 5910 890 2220

Installing tools (5910 890 2220) supplied from the
factory in future will have additional holes                                                  17
                                                                                18

(8 x 5.5 mm and 2 x 6.5 mm).                                                                       17

Any existing installing tools which do not have these ho-                                               18
les can be updated using the true-to-scale
                                                                          16
template on the last page of this TI bulletin:

Make a copy of the template, cut it out, put it on                                                       16
the underside of the flange and mark the holes.
After drilling the holes, mark them with the                         18
                                                                                                         18

appropriate numbers on the upper side of the
flange (see illustration).                                                     16

Stamp new notches and the numbers 16 and
17 on the outside edge of the flange.
                                                            fo                      17   16
                                                                                                    16

                                                                                                                     250TI009 KN
The illustration on the right shows the upper side
of the latest flange.

5.2=====Servicing aids

Part Name                   Part No.          Application                                                        Rem.

Carburetor parts kit        4134 007 1060     Zama C1Q-S34A,
                                              Zama C1Q-S36B
Set of gaskets              4128 007 1050     FS 400, 450
Set of gaskets              4134 007 1050     FS 120, 200, 350

Lubricating grease

(370 g/13 oz tube)          0781 120 1111     Oil seals
Dirko sealant               0783 830 2120     Crankcase sealing faces
(100 g/3.5 oz tube)

Training chart
FS 400, 450                 0457 256 0075     Service training

Standard commercial                            Cleaning crankshaft stub
solvent-based degreaser
containing no chlorinated
or hydrogenated
hydrocarbons
)42.97 - 8

6.=======Repairs

Note:=ff the unit is started up in the course of repairs or maintenance work, it is essential to strictly
observe all local and national safety regulations and the safety precautions outlined in the owner’s manual.
A service manual is available for servicing and repair procedures.
The service manual does not include the chapters "Servicing the Carburetor", "Troubleshooting" or any
repairs involving standard procedures. Such repairs are described in separate handbooks.

6.1======Setting data

6.1.1=For Zama C1Q-S34A and C1Q-S36B carburetors 

This carburetor does not have a high speed adjusting screw (H screw) or a low speed adjusting screw

(L screw).
The carburetor is set at the factory for an optimum fuel-air mixture under all operating conditions.
Restricting the idle mixture flow rate helps keep emissions under control when the engine is idling or running

at part load.

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• Mount the cutting tool
=====If nylon cutting head is fitted

     on the deflector.
     Adjust length of nylon lineK=Each line must extend as far as line limiting blade
                                                                                               LD -
                                                                                                   +
• Check air filter and fit a new one if necessary.

                                                                                                               250TI011 KN
• Check spark arresting screen and clean or replace as necessary.

     Start and warm up the engine.

Use /' to set idle speed to 2,800 rpm.

If running problems occur, make the following adjustments

Engine accelerates poorly, runs erratically at idle speed, stops during transition from full load to idle
or after long period of idling
Turn the idle speed screw (/') slowly clockwise until the engine runs smoothly -

cutting tool must not rotate.

Cutting tool rotates when engine is idling

Turn LD=counterclockwise until cutting tool stops rotating - then about another one full turn in the same
direction from that position.
)===================================================================================================42.97 - 

6.2======Testing data

6.2.1====Leakage test

6.2.1.1=Engine

- at gauge pressure:                     0.5 bar (7.25 psi)
- under vacuum:                          0.5 bar (7.25 psi)

6.2.1.2=Carburetor

- Inlet needle testing pressure:         0.8 bar (11.6 psi)

6.3======Tightening torques

Tightening torques are listed in the service manual for models FS 120, 200, 350, 400, 450.

6.4=====Repair times

The specified repair times assume that the work is performed by trained personnel in a properly equipped
service workshop.
The repair times are given in tenths of an hour (0.1 = 6 minutes).
Note:=qhe table for the new brushcutters/clearing saws can be added to the STIHL repair times table booklet.

7.======Spare Parts

Illustrated parts lists are available for the new models.
)42.97 - 10

FS 120, FS 200, FS 350, FS 400, FS 450
Warranty Repair Times

      Code    Type of Repair                    FS 120     FS 350       FS 400
                                                FS 200                  FS 450

      1       Crankcase, short block          1.6        1.6          1.6
      2       Crankshaft and/or bearings      1.6        1.6          1.6
      3       Crankcase gasket, sealing       1.6        1.6          1.6

      4       Crankshaft seals                1.0        1.0          1.0

      5       Cylinder and/or piston          0.9        0.9          0.9
      6       Ignition                        0.5        0.5          0.5
      7       Fuel hose, fuel supply          0.3        0.3          0.3

      8       Gear box, arbor assy            0.3        0.3          0.3
      9       Carburetor                      0.7        0.7          0.7
      10      Fan housing, clutch housing     0.4        0.5          0.5

      11      Front handle, throttle          0.4        0.4          0.4
      12      Recoil starter                  0.4        0.4          0.4
      13
      14
              Clutch
              Drive tube, drive shaft
                                              0.4
                                              0.4
                                                         0.5
                                                         0.5
                                                                fo    0.5
                                                                      0.5
      15      Muffler                         0.3        0.3          0.3
      16      Air filter, filter cover        0.2        0.2          0.2
      17      Stop switch                     0.3        0.3          0.3

      18      Fuel tank                       0.3        0.3          0.4
      19      Replacearbor gears              0.6        0.6          0.6
      20      Misc. repairs
                                         ✂    0.5        0.5          0.5

              Repair times are in tenths of

              an hour (0.1 = 6 minutes)

                                                               Andreas Stihl D1/MTK-na   6165
      © 1997 Andreas Stihl                                     Technical Documentation

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                        250TI012 KN
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