Instruction manual
FS 55, FS 55 C, FS 55 R, FS 55 RC
English
26
Exhaust emissions are controlled by the 
design of the fundamental engine 
parameters and components (e.g. 
carburation, ignition, timing and valve or 
port timing) without the addition of any 
major hardware.
The carburetor comes from the factory 
with a standard setting.
This setting provides an optimum fuel-air 
mixture under most operating 
conditions.
With this carburetor it is only possible to 
adjust the high speed screw within fine 
limits.
Standard Setting
N Stopping the Engine
N Mounting the cutting attachment
N Check the air filter and replace it if 
necessary.
N Have the spark arrestor checked – 
see “Inspection and Maintenance 
by Dealer"
N Turn high speed screw (H) 
counterclockwise as far as stop (no 
more than 3/4 turn).
N Turn the low speed screw (L) 
carefully clockwise as far as stop, 
then turn it back 1.5 turns.
N Start and warm up the engine if 
necessary.
N Adjust idle speed with the idle speed 
screw (LA) so that the cutting 
attachment does not rotate.
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 cutting attachment.
Engine Management Adjusting the Carburetor
L
H
LA
233BA050 KN










