Husqvarna TC 250 2021 Owner's Manual page 105

If the engine stutters when accelerating with a partially open throttle slide, the jet needle must be lowered. If the
engine knocks when accelerating at the full power rpm range, the jet needle must be raised.
Cylindrical part of the needle CYL
The cylindrical part of the needle has the greatest influence when the throttle slide is almost closed.
Idling jet IJ
The idling jet has the greatest influence in the low to mid throttle slide range.
If the engine stutters at idle speed or when accelerating with a partially open throttle slide, a smaller idling jet
must be used. If the engine knocks in this power range, then a larger idling jet must be used.
Idle air adjusting screw open ASO
The idle air adjusting screw has the greatest influence at idle speed.
Influence of throttle slide adjustment
The idling jet has the greatest influence when the throttle slide is closed. The first cylindrical part of the needle
and the clip position have only minimal influence.
When the throttle slide is 1/8 open, the first cylindrical part of the needle, the idling jet and the clip position
have the greatest influence.
When the throttle slide is 1/4 open, the idling jet and the clip position have the greatest influence. The influence
of the first cylindrical part of the needle is less.
When the throttle slide is 1/2 open, the position of the needle has the greatest influence. The influence of the
main jet and the idling jet is only minimal.
When the throttle slide is 3/4 open, the influence of the main jet is greatest. The clip position and the idling jet
have only minimal influence.
When the throttle slide is fully open, the influence of the main jet is greatest. The clip position and the idling jet
have only minimal influence.
TUNING THE ENGINE 15
K00495-01
K00496-01
K00497-01
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