Stihl FS 55 Instruction Manual page 30

English
Standard Setting – FS 55 2-MIX
H L
LA
Turn high speed screw (H)
N
counterclockwise as far as stop (no
more than 3/4 turn).
Turn the low speed screw (L)
N
carefully clockwise until it is against
its seat, then it back it off a 3/4 turn.
Adjusting Idle Speed – All Models
Carry out the standard setting.
N
Start and warm up the engine.
N
Engine stops while idling
Turn the idle speed screw (LA)
N
slowly clockwise until the engine
runs smoothly – the cutting
attachment must not rotate.
28
Cutting attachment rotates when engine
is idling
Turn the idle speed screw (LA)
N
counterclockwise until the cutting
attachment stops moiving and then
turn the screw another 1/2 to 1 full
turn in the same direction.
WARNING
If the cutting attachment continues to
rotate when the engine is idling, have
your machine checked and repaired by
your servicing dealer.
Erratic idling behavior, poor acceleration
(despite correction to setting of LA
screw).
Idle setting is too lean
FS 55
Rotate the low speed screw (L)
N
slowly about 1/4 turn
counterclockwise until the engine
runs and accelerates smoothly.
FS 55 2-MIX
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
FS 55
Rotate the low speed screw (L)
N
slowly about 1/4 turn clockwise until
the engine runs smoothly and still
accelerates satisfactorily.
FS 55 2-MIX
Turn the low speed screw (L) slowly
N
clockwise, no further than stop, until
the engine runs and accelerates
smoothly.
It is usually necessary to change the
setting of the idle speed screw (LA) after
every correction to the low speed
screw (L).
Fine Tuning for Operation at High
Altitude
A slight correction of the setting may be
necessary if engine does not run
satisfactorily:
Carry out the standard setting.
N
Warm up the engine.
N
Turn high speed screw (H) slightly
N
clockwise (leaner) – no further than
stop.
NOTICE
After returning from high altitude, reset
the carburetor to the standard setting.
If the setting is too lean there is a risk of
engine damage due to insufficient
lubrication and overheating.
FS 55, FS 55 C, FS 55 R, FS 55 RC