Polaris TX Starfire Owner's Manual page 78

CARBURETORS (Con't.)
DEGREE OF OPENING: 1/8- 1/4, air screw, throttle valve
When the cutaway of the throttle valve is made larger, the neg-
ative pressure which works on the needle jet reduces, and the
fuel-air mixture becomes lean.
When the cutaway of the throttle valve is made smaller, the
negative pressure which works on the needle jet becomes rich.
The cutaways are prepared at intervals of 0.5 m/m alternately.
(Note) The adjustment of the opening can be made either by
the throttle valve or the air screw. However, so far as the idling
is not in disorder, make adjustment by the air screw.
DEGREE OF OPENING: 1/4- 3/4, jet needle
The jet needle has 5 levels of groove. When the grip goes upward
(2nd & 1st levels) the space between the jet needle and the
needle jet becomes smaller and the fuel-air mixture becomes
lean.
When the grip goes downward, the space between the jet
needle and the needle jet becomes larger and the fuel-air mix-
ture becomes rich.
DEGREE OF OPENING: 3/4- full open, main jet
When the larger number is used, the fuel-air mixture becomes
rich. When the smaller number is used, the fuel-air mixture
becomes lean.
CHECK AND ADJUSTMENT OF THE FLOAT SYSTEM
The overflow during driving or operation of the engine could be
caused by a loose attachment due to worn needle valves, the
clog of dirt and dust, and the malfunctioning of the float, etc.
Needle Valve- Worn.
Spring is damaged or worn - replace with a new one.
Spring seat is worn or scratched.
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