Craftsman 917.259172 - Manual (Page 26)

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 requit ed to compensate for differences in fuel,
temperature, altitude or ioad. 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/
ait 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 SETTINQ -
«> 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 (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.
screw
tain 900 to'l 200 RPM.
Continue to hold throttle lever against idle speed
and adjust idle speed screw to obtain 900 to 1200
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 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.
IDLE MIXTURE
SCREW
THROTTLE
LEVER
FIG. 35
26