Craftsman 917.252560 manual Service and Adjustments, To Adjust Carburetor, See Figs, Final Setting

SERVICE AND ADJUSTMENTS

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TO ADJUST CARBURETOR

(See Figs. 32 and 33)

The carburetor has been preset at the factory and adjust- ment should not be necessary° However, minor adjust- ment may be required to compensate for differences infuel, temperature, altitude or Ioado 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)_

oWith 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 (N) 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 resulL

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

IDLE SPEED

SCREW

IDLE MIXTURE

SCREW

THROTTLE

LEVER

FIG. 32

IDLE SPEED __ _t_

THROTrLE	\ IDLE MIXTURE
LEVER	SCREW

FIG, 33

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