Stihl FS 87 Instruction Manual page 31

H L
LA
Carefully turn both adjusting screws
N
counterclockwise as far as stop:
The high speed screw (H) is 3/4 turn
–
open.
The low speed screw (L) is 3/4 turn
–
open.
Start and warm up the engine.
N
Adjust idle speed with the idle speed
N
screw (LA) so that the cutting
attachment does not move.
Adjusting Idle Speed
It is usually necessary to change the
setting of the idle speed screw (LA) after
every correction to the low speed screw
(L).
Warm up the engine for about 3
N
minutes.
Engine stops while idling
Turn the idle speed screw (LA)
N
slowly clockwise until the engine
runs smoothly – the cutting
attachment must not move.
Cutting attachment runs when engine is
idling
Turn the idle speed screw (LA)
N
counterclockwise until the cutting
attachment stops running and then
turn the screw about another 1/2 to
3/4 turn in the same direction.
FS 87, FS 87 R
If the working tool or cutting attachment
continues to run when the engine is
idling, have your machine checked and
repaired by your servicing dealer.
Erratic idling behavior, engine stops
even though setting of LA - screw has
been corrected, poor acceleration
Idle setting is too lean:
Turn the low speed screw (L)
N
counterclockwise, no further than
stop, until the engine runs and
accelerates smoothly.
Erratic idling behavior
Idle setting is too rich
Turn the low speed screw (L)
N
clockwise, no further than stop, until
the engine runs and accelerates
smoothly.
Version B: Fine Tuning
A slight correction of the setting of the
high speed screw (H) may be necessary
if engine power is not satisfactory when
operating at high altitude, sea level or
after changing the working tool/cutting
attachment.
Rule of thumb:
Turn the high speed screw (H) about
one quarter turn for every 1000m (3300
ft) change in altitude.
Conditions for adjustment
Carry out the standard setting
N
without disturbing the high speed
screw (H).
Warm up the engine for about 3
N
minutes.
Open the throttle wide.
N
At high altitude
Turn the high speed screw (H)
N
clockwise (leaner), no further than
stop, until there is no further
noticeable increase in engine
speed.
At sea level
Turn the high speed screw (H)
N
counterclockwise (richer), no further
than stop, until there is no
noticeable increase in engine
speed.
It is possible that maximum engine
speed may be reached with the standard
setting.
English
29