32
English / USA
FS 300, FS 350, FS 400, FS 450, FS 480
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.
General Information
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
: Shut off the engine.
: Mount approved cutting tool.
: Check the air filter and replace if 
necessary.
: Check adjustment of the throttle 
cable and readjust if necessary – 
see "Adjusting the Throttle Cable".
: Turn high speed screw (H) 
counterclockwise (max. 
3
/
4
  turn) as 
far as stop.
: Carefully screw the low speed 
screw (L) down onto its seat. Then 
open it one turn counterclockwise.
: Start the engine and run it until it is 
warm.
: Adjust idle speed with the idle speed 
screw (LA) so that the cutting tool 
does not rotate.
Motor Management Adjusting the Carburetor
255BA001 KN
LA
1
L
H
3/4