Sears 917.250551 - Manual (Page 26)

SERVICE AMD ADJUSTMENTS
TO ADJUST CARBURETOR (See Fig. 33)
The carburetor has been present at the factory and adjust­
ment should not be necessary . However, minor adjustment
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 adjusting needles in (clockwise)
decreases the supply of fuel to the engine giving a leaner
fuel/air mixture. Turning the adjusting needles out (coun­
terclockwise) 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 is adjusted properly (see ‘TO ADJUST
THROTTLE CONTROL CABLE" in the Service and
Adjustments section of this manual),
® With engine off turn idle fuel adjusting needle irr (clock­
wise) closing it finger tight and then turn out (counter­
clockwise) 1 turn.
FINAL SETTING -
° Start engine and allow to warm for five minutes. Make
final adjustments with engine running and shifl/motion
control lever in neutral (N) position.
“ The high idle is set at the factory and cannot be
adjusted.
° Idle speed setting - With throttle control lever in slow
{ - & ) position, engine should idle at 1200 RPM. If
engine idles too slow or fast, turn idle speed adjusting
screw in or out until correct idle is attained.
“ Idle fuel needle setting - With throttle control lever in
slow { ■ m ) position, turn idle fuel adjusting needle in
(clockwise) until engine speed decreases and then
turn out (counterclockwise) approximately 3/4 turn to
obtain the best low speed perlormance.
" Recheck idle speed. Readjust if necessary.
ACCELERATION TEST -
*> Move throttle control lever from slow (*«f) to fast (•%)
position. If engine hesitates or dies, turn idle fuel
adjusting needle out (counterclockwise) 1/8 turn. Re­
peat test and continue to adjust, if necessary, until
engine accelerates 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. OVERSPEEDING THE 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/
DEPARTMENT, WHICH HAS PROPER EQUIPMENT AND
EXPERIENCE
TO MAKE ANY NECESSARY
ADJUSTMENTS
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