To Adjust Carburetor - Craftsman 917.259566 Owner's Manual

SERVICE AND ADJUSTMENTS
TO ADJUST CARBURETOR (See Figs. 34 &
35)
The carburetor has been preset at the factory and adjust-
ment should not be necessary. However, minor adjust-
ment may be requiredto compensatefor differencesinfuel,
temperature, altitude or load. If the carburetor does need
adjustment,proceed as follows:
In general, turning the mixture screw in (clockwise) de-
creases the supplyof fuel tothe engine givinga leanerfuel/
air mixture. Turning the mixturescrew out (counterclock-
wise) increases the supply of fuel to the engine giving a
richerfuel/air mixture.
IMPORTANT: DAMAGE TO THE NEEDLES AND THE
SEATS IN CARBURETOR MAY RESULT IF SCREW IS
TURNED IN TOO TIGHT.
PRELIMINARY SETI'ING -
• Be sure you have a clean air filter, and the throttle
control cable and choke are adjusted properly (see
above).
With engine offturn idle mixture screw in (clockwise)
closingit finger tight and then turn out (counterclock-
wise) 1-1/4 to 1-1/2 turns.
FINAL SETTING -
• Start engine and allowto warmforfive minutes. Make
final ad ustmentswithengine runningand shift/motion
controllever in neutral (N) positon.
• With throttlecontrol 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 ad ust idle speed screwto obtain 900 to 1200 RPM.
Re ease thrott e ever.
ACCELERATION TEST -
• Move throttlecontrol lever from slowto fast position. If
engine hesitates or dies, turn idle mixturescrew out
(counterclockwise)1/8turn. Repeat test andcontinue
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 THINKTHE 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
LEVER
FIG. 34
LEVER SCREW
FIG. 35
25