Stihl FC 91 User Manual

FC 91
English
20
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 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.
N If the engine is down on power,
check the spark arresting screen in
the muffler.
N Wait for the muffler to cool down.
N Take out the screw (4).
N Lift the spark arresting screen (5)
and pull it out.
N Clean the spark arresting
screen (5). If the screen is damaged
or heavily carbonized, install a new
one.
N Refit the spark arresting screen (5).
N Insert the screw (4) and tighten it
down firmly.
Engine Management Adjusting the Carburetor
0000-GXX-0495-A0
Spark Arresting Screen in
Muffler
0000-GXX-0486-A0
4
5

Stihl FC 91 Specifications

General

Brand	Stihl
Model	FC 91
Category	Trimmer
Language	English