OPERATION
Page 8 of 18
Carburetor Adjustment
High Speed
Low Speed
Idle Needle
Idle Needle
The carburetor is factory adjusted, but may require
readjustment, especially for cold weather operation or
high altitudes.
If the fuel mixture is too lean, a cold engine may stall
under a load. If the engine stalls as soon as the throttle
opens, the ``idle mixture'' may be too lean. If the engine
speeds up when the throttle opens, but stalls when the
pump primes, then the ``high speed'' adjustment is prob‐
ably too lean.
1.
Turn both adjustment needles clockwise until com‐
pletely closed.
CAUTION
Carburetor needle adjustment
may result in seat damage.
Do not force adjustment needles tightly closed or the
seat could be damaged.
2.
Open both needles by turning counterclockwise one
turn. This will be a rich setting and operation under a
load will determine the best setting.
3.
Adjust the low speed idle needle first, and accelerate.
If the engine bogs down or accelerates slowly, turn the
low speed idle needle clockwise until performance is
acceptable. If the engine stalls on acceleration, turn
the low speed idle needle counterclockwise until per‐
formance is satisfactory. The average low speed idle
needle adjustment is one turn open.
4.
Adjust the high speed needle next. Turn the high
speed needle clockwise until engine runs smoothly.
DO NOT go any leaner than necessary on the high
speed adjustment as piston seizure can occur at high
speed. The average high speed needle adjustment is
one turn to open. This will vary according to outside
temperature. Low temperatures generally require
richer settings. (Adjust screw counterclockwise.)
5.
If the engine runs too fast at idle speed, turn the idle
stop screw counterclockwise until the desired idling
speed is obtained. To increase idling speed, turn the
idle stop screw clockwise.
