To adjust carburetor (see figs. 41 and 42), Service and adjustments – Sears 917.25597 User Manual
Page 25
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SERVICE AND ADJUSTMENTS
TO ADJUST CARBURETOR
(See Figs. 41 and 42)
The carburetor has been preset at the factory and ad|ust-
ment should not be necessary. However, minor adjust
ment may be required to compensate for differences in fuel,
temperature, altitude or load. If the carburetor does need
adjustment, proceed as follows:
In general, turning the mixture screw
in
(clockwise) de
creases the supply of fuel to the engine giving a leaner fuel/
air mixture. Turning the mixture screw
out
(counterclock
wise) increases the supply of fuel to the engine giving a
richer fuel/air mixture.
IMPORTANT:
DAMAGE TO THE NEEDLES AND THE
SEATS IN CARBURETOR MAY RESULT IF SCREW IS
TURNED IN TOO TIGHT
PRELIMINARY SETTING -
» Be sure you have a clean air filter, and the throttle
control cable and choke are adjusted properly (see
above).
» With engine off turn idle mixture screw
in
(clockwise)
closing it finger tight and then turn
out
(counterclock
wise) 1-1/4 to 1-1/2 turns.
FINAL SETTING -
» Start engine and allow to warm for five minutes. Make
final adjustments with engine running and shift/motion
control lever in "NEUTRAL" position.
® With throttle control lever in "SLOW" position, hold
throttle lever against idle speed screw and adjust idle
speed screw to obtain 1200 to 1400 RPM.
• While still holding throttle lever against idle speed
screw, turn idle mixture screw
in
(clockwise) until
engine begins to die and then turn
out
(counterclock
wise) until engine runs rough. Turn screw to a point
midway between those two positions.
<• Continue to hold throttle lever against idle speed screw
and adjust idle speed screw to obtain 900 to 1200 RPM.
Release throttle lever.
.ACCELERATION TEST -
• Move throttle control lever from "SLOW" to "FAST"
position. If engine hesitates or dies, turn idle mixture
screw
out
(counterclockwise) 1/8 turn. Repeat test
and continue to adjust, if necessary, until engine accel
erates smoothly.
High speed stop is factory adjusted. Do not adjust -
damage may result.
IMPORTANT:
NEVER TAMPER WITH THE ENGINE
GOVERNOR, WHICH IS FACTORY SET FOR PROPER
ENGINE
SPEED.
OVERSPEEDINQTHE
ENGINE
ABOVE
THE
FACTORY
HIGH
SPEED
SETTING
CAN
BE
DANGEROUS. IF YOU THINK THE ENGINE-GOVERNED
HIGH
SPEED
NEEDS
ADJUSTING,
CONTACT
YOUR
NEAREST AUTHORIZED SERVICE CENTER, WHICH HAS
PROPER EQUIPMENT AND EXPERIENCETO MAKE ANY
NECESSARY ADJUSTMENTS.
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