Sears 917.25597 Lawn Mower User Manual


 
$ERVRCE AND ADJUSTMENTS
i ,,,=
TO ADJUST CARBURETOR
(See Figs. 41 and 42)
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 in fuel,
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 rN TOO TIGHT.
PRELIMINARY SETTING -
o 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 allowto warm for five minutes. Make
final adjustments with engine running and shift/motion
control lever in "NEUTRAL" position.
o With throttle control lever in "SLOW" position, hold
throttle lever against idle speed screw and adjust idle
speed screw to obtain 1200 to 1400 RPMo
o 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.
o Continue to hold throttle lever against idle speed screw
and adjust idle speed screwto obtain 900 to 1200 RPM
Release throttle lever.
,ACCELERATION TES]: -
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. OVERSPEEDINGTHE ENGINE ABOVE
THE FACTORY HIGH SPEED SETTING CAN BE
DANGEROUS,, IF YOU THINKTHE ENGINE-GOVERNED
HIGH SPEED NEEDS ADJUSTING, CONTACT YOUR
NEARESTAUTHORtZED SERVICE CENTER, WHICH HAS
PROPER EQUIPMENT AND EXPERIENCE TO MAKE ANY
NECESSARY ADJUSTMENTS..
IDLE SPEED
SCREW
IDLE MIXTURE
SCREW
THROTTLE
LEVER
FIG. 41
IDLE MIXTURE
LEVER SCREW
FIG. 42
2S