FS 91, FS 91 R
English
38
Filters have an average life of more than 
a year. Do not remove the filter cover or 
replace the air filter as long as there is no 
noticeable loss of power.
If there is a noticeable loss of engine 
power
N Turn the choke knob to g.
N Loosen the screws (1).
N Remove the filter cover (2). 
N Clean away loose dirt from around 
the filter.
N Remove the filter element (3).
N Replace dirty or damaged filter 
element (3).
N Replace any damaged parts.
Installing the Filter Element
N Install the filter element (3) in the 
filter housing and fit the cover.
N Insert the screws (1) and tighten 
them down firmly.
Exhaust emissions are controlled by the 
design of the engine and components 
(e.g. carburation, ignition, timing and 
valve or port timing).
The carburetor has been set at the 
factory to provide an optimum fuel-air 
mixture under most operating 
conditions.
Adjusting Idle Speed
Engine stops while idling
N Warm up the engine for about 
3 minutes.
N Turn the idle speed screw (LA) 
slowly clockwise until the engine 
runs smoothly – the cutting 
attachment must not run.
Cutting attachment runs when engine is 
idling
N Turn the idle speed screw (LA) 
slowly counterclockwise until the 
cutting attachment stops running 
and then turn the screw about 
another 1/2 to 3/4 turn in the same 
direction.
WARNING
If the cutting attachment continues to run 
when the engine is idling, have your 
machine checked and repaired by your 
servicing dealer.
Replacing the Air Filter
Engine Management Adjusting the Carburetor