Stihl 85 Manual

40 English / USAFS 80, FS 80 R, FS 85, FS 85 R
Rule of thumb
Turn high speed screw 
(H) about 
1/4  turn over for every 1000m 
(3.300 ft) change in altitude.
Conditions for adjustment
Adjust the high speed screw  (H) 
only if you are using a mowing head, 
making sure the cutting lines are full 
length (as far as the limiter blade on 
the deflector).
If you mount a metal cutting tool, 
use the standard setting.
: Carry out standard setting without 
changing position of high speed 
screw  (H).
: Warm up...

41
FS 80, FS 80 R, FS 85, FS 85 R English / USA
If the engine is low on power, check the 
spark arresting screen in the muffler.
: Lift spark arresting screen and pull it 
out sideways.
: Clean spark arresting screen if 
necessary.
: If screen is damaged or coked up, fit 
a new one.
: Refit the spark arresting screen.
* see “Guide to Using this Manual” Wrong fuel mix (too much engine oil in 
the gasoline), a dirty air filter and 
unfavorable running conditions (mostly 
at part throttle etc.) affect the...

42 English / USAFS 80, FS 80 R, FS 85, FS 85 R
To reduce the risk of fire and burn 
injury, use only spark plugs 
authorized by STIHL. Always press 
spark plug boot 
(2) snugly onto 
spark plug terminal  (1) of the proper 
size. (Note: If terminal has 
detachable SAE adapter nut, it must 
be attached.) 
A loose connection between spark 
plug boot and ignition wire 
connector in the boot may create 
arcing that could ignite combustible 
fumes and cause a fire. :
Check grease level regularly - about...

43
FS 80, FS 80 R, FS 85, FS 85 R English / USA
Removing the Rope Rotor
:
Take out the screw ( 5).
: Remove the rope rotor very 
carefully.
The rewind spring is seated in the 
rope rotor and may pop out and 
uncoil if care is not taken. 
The pieces of broken spring may be 
under tension and fly apart 
unexpectedly when you remove the 
rope rotor. To help reduce the risk of 
injury, wear face protection and 
gloves.
Replacing the Starter Rope
:Use a screwdriver to pry the cap ( 6) 
out of the starter...

44 English / USAFS 80, FS 80 R, FS 85, FS 85 R
:
Carefully remove the parts of the old 
spring from the starter cover and 
rope rotor.
: Insert the new rewind spring in the 
rope rotor and, at the same time, 
engage the outer spring loop in the 
rotor’s recess – the wire retainer 
slips off in this process. 
If the spring pops out and uncoils, 
refit it in the counterclockwise 
direction, starting outside and 
working inwards.
: Go to Installing the Rope Rotor.
Installing rope rotor with rewind 
spring...

45
FS 80, FS 80 R, FS 85, FS 85 R English / USA
Fitting the Starter Cover
:
Push the upper mounting boss ( 2) 
under the shroud ( 4) –
line up the tank ( 3)and push the 
lower part of cover onto the tank.
: Insert and tighten down the housing 
screws ( 1). For periods of about 3 months or longer
:
Drain and clean the fuel tank in a 
well ventilated area.
: Dispose fuel properly in accordance 
with local environmental 
requirements.
: Run engine until carburetor is dry – 
this helps prevent carburetor...

46 English / USAFS 80, FS 80 R, FS 85, FS 85 R
:
Resharpen the cutters  (1) uniformly 
– do not alter the contour of the 
parent blade  (2) in any way.
See cutting tool packaging for additional 
sharpening instructions.
22
1
2
11
002BA042 KN 

47
FS 80, FS 80 R, FS 85, FS 85 R English / USA
1) STIHL recommends that this work be done by a
   STIHL servicing dealer
*  Not in all versions, market-specific
Maintenance Chart
Please note that the following maintenance intervals apply for normal operating 
conditions. If your daily working time is longer than normal or cutting conditions 
are difficult (very dusty work area etc.), shorten the specified intervals accordingly.
before 
starting work
after finishing 
work or daily
after each
refueling...

48 English / USAFS 80, FS 80 R, FS 85, FS 85 R
Please note that the following maintenance intervals apply for normal operating 
conditions. If your daily working time is longer than normal or cutting conditions 
are difficult (very dusty work area etc.), shorten the specified intervals accordingly.
before 
starting work
after finishing 
work or daily
after each
refueling stop
weekly
monthly
every 12 months
if problem
if damaged
as required
Cutting toolsInspect
XX
Replace X
Check tightness  
of cutting...

49
FS 80, FS 80 R, FS 85, FS 85 R English / USA
   1 Fuel pump
   2 Choke lever
   3 Carburetor adjusting screws
   4 Starter grip
   5 Fuel filler cap
   6 Fuel tank
   7 Muffler
(with spark arresting screen*)
   8 Throttle trigger
   9 Slide control
10 Throttle trigger interlock
11 Bike handle
12 Handle support
13 Throttle cable retainer
14 Clamp 
(carrying ring for harness)
15 Spark plug boot
16 Air filter cover
17 Machine support
18 Barrier bar,
not in all versions, market-specific
19 Loop handle
20...