Carburetor - Adjust Idling; Basic Information On Carburetor Wear; Adjusting The Mixture Control Screw - HUSABERG Edition 2004 Owner's Manual

MAINTENANCE WORK ON CHASSIS AND ENGINE
CARBURETOR – ADJUST IDLING *
Idling adjustment of the carburetor strongly affects the engine's
starting behavior. That is, an engine whose idling speed is adjusted
correctly will be easier to start than one whose idling speed has not
been adjusted correctly.
The idle speed is controlled by means of the adjusting wheel (1)
and the mixture control screw (2). The adjusting wheel is used to
adjust the basic setting of the slide. The mixture control screw is
used to control the idle mixture which arrives at the engine by way
of the idle system. Clockwise turning reduces the fuel quantity (lean
mixture), counterclockwise turning increases the fuel quantity (rich
mixture).
TO ADJUST IDLING CORRECTLY, PROCEED AS FOLLOWS:
1 Turn in mixture control screw (2) up to the stop, and turn it back
out to the basic position (see technical date-engine)
2 Warm up the engine
3 Use the adjusting wheel (1) to set the normal idle speed (1400 - 1500 rpm).
4 Turn mixture control screw (2) slowly clockwise until idling speed
starts to decrease. Memorize this position, and turn mixture con-
trol screw slowly counterclockwise until the idling speed decrea-
ses again. Adjust the point of the highest idling speed between
these two positions. If, in the course of this procedure, the
speed undergoes a relatively high increase, reduce the idle
speed to a normal level and repeat the procedure specified in 4.
Serious competitive racers will choose a setting approx. 1/4 turn
(clockwise) leaner than this ideal value because their engine will
heat up more when used in competitions.
NOTE: If you fail to obtain a satisfying result by following
the procedure described above, an incorrectly dimensio-
ned idling nozzle may be the cause. If:
a) the mixture control screw has been screwed in up to
the stop without causing any change in rotational speed,
a smaller idling jet has to be installed;
b) the engine dies when the mixture control screw is still
open by 2 turns, a larger idling jet needs to be selected.
Naturally, in cases of jet changes, you have to start your
adjusting work from the beginning.
5 Then, use the adjusting wheel to set the desired idle speed.
6 In cases of greater changes in the outside temperature and
extremely different altitudes, the idling speed should be readju-
sted.

BASIC INFORMATION ON CARBURETOR WEAR

As a result of engine vibrations, the throttle valve, jet needle, and
needle jet are subjected to increased wear. This wear may cause
the carburetor to malfunction (e.g., overly rich mixture). Therefore,
these parts should be replaced after 200 hours.

ADJUSTING THE MIXTURE CONTROL SCREW *

The mixture control screw is used to adjust the idle mixture.
Turning the mixture control screw in a clockwise direction will
reduce the idle mixture, turning it in a counterclockwise direction
will increase the idle mixture.
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