Adjusting The Carburetor; Basic Setting - Stihl FS 94 Instruction Manual

1
: Check needle (arrow) for
damage or wear, replace low
speed screw L (1) if necessary –
the needle must be perfectly
straight.
1
: Carefully push the low speed
screw L (1) into the bore (arrow)
and screw it home – take care not
to bend the needle.
2
1
: Position sleeve (1)
5910 893 1711 on the control
valve lever so that it engages the
teeth (arrow).
76
: Insert screwdriver (2)
5910 890 2311 through the
sleeve (1) and locate it on the hex
head of the low speed screw L.
: Hold the sleeve (1) steady and
screw home the low speed
screw L as far as stop.
– Continue with the high speed
screw H.
High speed screw
1
: Use screwdriver (1)
5910 890 2311 to remove the
high speed H (arrow).
1
: Inspect the tip (arrow) for
damage or wear and replace the
high speed screw H (1) if
necessary.
– Screw down the high speed
screw (H) as far as stop.
– Carry out the basic setting,
b 10.5.1
10.5

Adjusting the Carburetor

The new carburetors are tuned at
the factory so that the engine
receives an optimum fuel-air
mixture in all environments and
operating conditions.
The high speed screw H and low
speed screw L can only be adjusted
with screwdriver 5910 890 2311.
It is no longer necessary or possible
for the user to change the settings
of these adjusting screws.
The user may adjust engine idle
speed with the idle speed screw LA.

10.5.1 Basic Setting

The basic setting is necessary only
if the high speed screw H or low
speed screw L has to be replaced
or after cleaning the carburetor.
A basic setting and fine tuning are
necessary after removing and
installing the adjusting screws.
The adjusting screws have to be
preset before starting fine tuning.
This can be performed while the
engine is stationary or on a
carburetor removed from the
machine.
Starting with the low speed and high
speed screws against their seats,
turn them counterclockwise.
Series 4149 Powerhead