Technical Information · issue 45 of 1999
FS 85 T: New Model FS 85 T
IssueTI 45/1999
Full text
Page 1 of 9
Technical Information
45.1999
New Model FS 85 T - Series 4137
Contents
1. Technical Description
2. Specifications
3. Tools
4. Accessories for User
5. Service Accessories
6. Repairs
7. Spare Parts
The FS 85 T brushcutter (T = split boom) is the first
STIHL standard power tool which can be equipped
with a line of attachments for land maintenance.
The quick-action coupling on the split boom (drive
tube) allows a number of different attachments from
the new STIHL Multi-Cut Professional Series to be
mounted.
This brushcutter therefore serves as the power unit
for several tools with a wide range of applications.
TI_45_1999_30_02.fm english / USA
)m~ge 2 Technical Information 45.1999
The following attachments are currently available:
FC, FH, HL (0°, 30° and 0 ... 90°) and HT (bike-
handle version is only suitable for use with
FH attachment).
The powerhead (basic engine 4137) and
ergonomically designed controls are exactly the
same as those of the FS 85.
1. Technical Description
Engine, controls and handle system as FS 85
Split boom / drive shafts
. Rigid shafts
. Quickly separated for interchanging
attachments
Gearhead
393TI005 KN
. As FS 80, 85
2. Specifications
2.1 Powerhead
2.1.1 Engine
Single cylinder two-stroke engine
Displacement: 25.4 cm3 (1.55 cu.in)
Bore: 34 mm (1.34 in)
Stroke: 28 mm (1.10 in)
Engine power to 0.95 kW (1.27 bhp)
ISO 8893: at 7,000 rpm
Engine speeds: see 2.1.2
Rewind starter: Single pawl system
Starter rope: 3 mm (0.12 in) dia., 800
mm (31.5 in) long
Clutch:
- engages at: 3,700 rpm
TI_45_1999_30_02.fm Page 2 of 9
Technical Information 45.1999 Page 3
2.1.2 Fuel System
Carburetor: All position diaphragm carburetor with integral fuel pump
Idle speed screw LD (standard setting) Open 2 full turns (see 6.1)
Idle speed 2,500 to 3,100 rpm
Cutoff speed range without cutting tool (electronic speed
governor) 9,700 to 11,300 rpm
Fuel tank capacity: 0.44 L (15 fl.oz)
Fuel mix: Mid grade gasoline (unleaded) and two-stroke engine oil
Mix ratio: 50:1 with STIHL 50:1 two-stroke engine oil
2.1.3 Ignition System
Ignition module: with integral electronic speed
governor
Spark plug Bosch WSR 6F,
(suppressed): NGK BPMR 7 A or
Champion RCJ 6Y
2.2 Weight
without cutting tool and deflector
FS 85 T: 5.4 kg (11.9 lb)
FS 85 RT: 5.2 kg (11.5 lb)
TI_45_1999_30_02.fm
)m~ge 4 Technical Information 45.1999
3. Tools
3.1 FS Cutting Tools
The following cutting tools are approved
1 2
1 STIHL Supercut 20-2 4002 710 2162
2 STIHL Autocut 21-2 4002 710 2113
3 STIHL Autocut 25-2 4002 710 2108
3 4
4 STIHL Trimcut 30-2 4002 710 2122
5 STIHL Polycut 20-3 4002 710 2130 5
6 Cutting blade 230-4* 4001 713 3801
7 Cutting blade 230-8* 4001 713 3803
8 Brush Knife 250-3* 4112 713 4100
9 Circular saw blade 200 4112 713 4201 6
(scratcher tooth)**
10 Circular saw blade 200 4112 713 4203
(chisel tooth)**
7 8
* Not approved for loop
handle FS 85 T without
barrier bar
** Approved only for
FS 85 T with bike handle 9 10
393TI014 KN
and double shoulder
harness
TI_45_1999_30_02.fm Page 3 of 9
Technical Information 45.1999 Page 5
3.2 Attachments
Standard power tools:
1 FS 85 RT with loop handle (shown without attachment)
2 FS 85 T with bike handle (shown without attachment)
3 FC edger FC*
4 FH power scythe
5 HL 0° hedge trimmer*
6 HL 30° hedge trimmer*
7 HL 0 ... 90° hedge trimmer*
8 HT pole pruner*
* For ergonomic reasons, not suitable on units with bike handle (see TI 50.98)
TI_45_1999_30_02.fm
)m~ge 6 Technical Information 45.1999
4. Accessories for User
Part Name Part No. Application
ElastoStart 0000 190 3400 Rewind starter (grip with rope)
Starter rope 0000 195 8200 Rewind starter, also for ElastoStart
STIHL gear lubricant for hedge Drive shafts in boom (tube)
trimmers
- 80 g (2.8 oz) tube 0781 120 1109
- 225 g (8 oz) tube 0781 120 1110
STIHL gear lubricant for Gearbox
brushcutters
- 80 g (2.8 oz) tube 0781 120 1117
- 225 g (8 oz) tube 0781 120 1118
5. Service Accessories
5.1 Special Servicing Tools
Special servicing tools are listed in the service manual for models FS 75, 80, 85, FC 75, HL 75.
5.2 Servicing Aids
Part Name Part No. Application
Carburetor parts kit 4227 007 1060 Zama C1Q S45
Lubricating grease 0781 120 1111 Oil seals
- 225 g (8 oz) tube
Dirko sealant 0783 830 2120 Engine pan/cylinder sealing faces
Electrician’s repair kit 5910 007 1050 Electrical system
Standard commercial solvent- Cleaning crankshaft stub
based degreasant containing no
chlorinated or hydrogenated
hydrocarbons
TI_45_1999_30_02.fm Page 4 of 9
Technical Information 45.1999 Page 7
6. Repairs
If the unit is started up in the course of repairs, it is essential to strictly observe all country-specific
safety regulations and the safety precautions outlined in the owner’s manual.
6.1 Carburetor Adjustment
Standard setting
. Mount approved cutting tool
. Check air filter and replace if necessary
. Carefully screw down the idle speed screw (LD)
counterclockwise (left-hand thread) until it is
against its seat, then open it two full turns
clockwise
LD
392TI028 KN
Adjusting idle speed
. Carry out standard setting
. Start and warm up the engine
Engine stops while idling:
. Turn the idle speed screw (LD) slowly clockwise until engine runs smoothly - the cutting tool must not rotate.
Cutting tool rotates while engine is idling:
. Turn the idle speed screw (LD) counterclockwise until the cutting tool stop rotating and then turn the screw
about another full turn in the same direction (counterclockwise).
Erratic idling behavior, poor acceleration:
. Turn the idle speed screw (LD) slowly counterclockwise no more than 1/2 turn until engine runs smoothly.
6.2 Lubricating/Replacing Shafts
6.2.1 Lower part of drive tube (boom)
3 2
. Release wing screw (1) and pull lower part of
drive tube (2) out of the coupling sleeve (3)
. Remove gearhead/attachment from the drive
tube
1
393TI008 KN
TI_45_1999_30_02.fm
)m~ge 8 Technical Information 45.1999
. Press down the locking button and hold it there.
Pull the shaft (4) with sleeve (5) out of the drive
tube (this is easier if you push from the other end
of the shaft)
If the shaft has turned blue, fit a new one.
. Coat drive shaft with STIHL gear lubricant for 5 4
hedge trimmers. Never pump grease into the
drive tube.
393TI009 KN
. Push the shaft (4) and sleeve (5) into the drive
tube
. Press down the locking button and push the
sleeve (5) in place as far as stop (locking button
must snap into position)
. Install the gearhead/attachment and line it up
properly
6.2.2 Upper part of drive tube (boom)
. Release the clamp screw (6) and pull the
coupling sleeve (7) off the drive tube. Press
down the locking button and hold it there. Pull
the shaft (8) with sleeve (9) out of the drive tube
If the shaft has turned blue, fit a new one. 6 7
. Coat drive shaft with STIHL gear lubricant for
hedge trimmers. Never pump grease into the
393TI010 KN
drive tube.
9 8
. Push the shaft (8) and sleeve (9) into the drive
tube. Press down the locking button and push in
the sleeve (9) as far as stop (locking button must
snap into position) - it may be necessary to turn
the shaft back and forth a little
9 8
. Push coupling sleeve (7) onto the drive tube as
far as stop so that the lug engages the slot. Line
up so that gap in clamp and machine support
face downwards
393TI011 KN
. Tighten the clamp screw (6) firmly
. Finish by installing the lower part of the drive
6 7
tube with the gearhead/attachment
TI_45_1999_30_02.fm Page 5 of 9
Technical Information 45.1999 Page 9
6.3 Tightening Torques .
The tightening torques for the FS 85 T are listed in Code Type of Repair FS 85 T
the service manual for models FS 75, 80, 85, FC 75,
1 Crankcase, Crankshaft, 2.0*
HL 75.
Crankshaft Bearings
2 Replace Short Block 1.0
3 Crankcase Gasket/Sealing 2.0
6.4 Service Note
4 Crankshaft Seals (includes 1.0
Service manual FS 75, 80, 85, FC 75, HL 75 is pressure & vacuum testing)
available for servicing the FS 85 T
5 Cylinder and/or Piston 1.0
This service manual does not include the chapters 6 Ignition Module 0.5
"Servicing the Carburetor", "Troubleshooting" or any 7 Fuel Hose 0.5
repairs involving standard procedures. Such
8 Replace Gear Box/Arbor Assy 0.5
procedures are described in separate handbooks,
i.e. “Carburetors” and "Standard Repairs, 9 Repair/Rebuild Carburetor 0.8
Troubleshooting". 10 Replace Carburetor, Carburetor 0.4
Jet (if tried to repair use code 9)
11 Front Handle, Throttle Control, 0.6
Throttle Cable
6.5 Repair Times
12 Recoil Starter 0.5
The specified repair times assume that the work is
13 Clutch, Clutch Drum, Clutch Drum 0.7
performed by trained personnel in a properly
Housing
equipped service workshop.
14 Drive Tube, Drive Shaft 0.5
15 Muffler 0.4
The repair times are given in tenths of an hour 16 Air Filter, Filter Cover, Tank Cap, 0.3
(0.1 = 6 minutes). Tank Vent, Fuel Filter, Spark Plug,
Cutting Attachment,
Miscellaneous Minor Repairs
Note: This table for model FS 85 T can be added to
17 Stop Switch 0.5
the STIHL repair times table.
18 Fuel Tank 0.4
19 Repair Gear Box, Gears, 0.8
Arbor Bearings
20 All Other Repairs 0.5
7. Spare Parts ✂
The FS 85 T and the attachments are included in the
illustrated parts lists of the respective single-
purpose units. * Recommend to replace with short block (code 2).
© 1999 Andreas Stihl AG & Co. Technical Documentation
Waiblingen D1/MTK-na 6782
TI_45_1999_30_02.fm Page 6 of 9
Page 7 of 9
Page 8 of 9
Page 9 of 9
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.