Mixture Control Valve Adjustment - O.S. engine MAX-25AX & MAX-35AX Instruction Manual

With the engine running, close the throttle and
allow it to idle for about five seconds, then
open the throttle fully. If, at this point, the
engine is slow to pick up and produces an
excess of exhaust smoke, the mixture is too
rich. Correct this condition by turning the
Mixture Control Screw clockwise 15-30
degrees. If the mixture is excessively rich,
engine rpm will become unstable: opening the
throttle will produce a great deal of smoke and
rpm may drop suddenly or the engine may
stop. This condition may also be initiated by
excessively prolonged idling. If,on the other
hand, the mixture is too lean, this will be
indicated by a marked lack of exhaust smoke
and a tendency for the engine to cut out when
the throttle is opened.
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MIXTURE CONTROL VALVE ADJUSTMENT

In this case, turn the Mixture Control Screw
counter-clockwise 90 degrees to positively
enrich the idle mixture, then turn the screw
clockwise gradually until the engine regains full
power cleanly when the throttle is reopened.
Carry out adjustments patiently until the
engine responds quickly and positively to the
throttle control.
Note: Mixture Control Valve adjustments
should be made in steps of 15-30˚
initially, carefully checking the effect,
on throttle response, of each small
adjustment.
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