Sears 917.256543 Lawn Mower User Manual


 
SERVnCE AN ADJUSTMENTS
ENGINE
TO ADJUST THROTTLE CONTROL CABLE
(See Fig. 32)
The throttle control has been preset at the factory and
adjustment should not be necessary° Check adjustmentas
described below before loosening cable_ If adjustment is
necessary, proceed as follows:
,, With engine not running, move throttle control lever
from slow [_) to choke (t'-.!) position. Slowly move
lever from choke (N) to fast (,_,) position.
- Check to see if hole in throttle lever and hole in speed
control bracket are aligned.
o If holes are not aligned, loosen cable clamp screw and
align the holes by inserting a pencil or a 1/4" drill bit
through both holes.,
Pull throttle cable up to remove slack and tighten cable
clamp screw. Remove alignment pencil or drilt bit..
TO ADJUST CARBURETOR (See Fig, 33)
The carburetor has been preset at the factory and adjust-
ment should not be necessary. However, minor adjust-
merit may be required to compensate for differences in fuel,
temperature, altitude or toad. 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 (counter-
clockwise) increases the supply of fuel to the engine giving
a richer fuel/air mixture..
IMPORTANT: DAMAGE TO THE NEEDLES AND THE
SEATS tN CARBURETOR MAY RESULT IF NEEDLE iS
TURNED IN TOO TIGHT..
NOTE: The carburetor on this engine is low emission_ it is
equipped with an idle fuel adjusting needle with a ]imiter
cap, which allows some adjustment within the Iimits allowed
by the cap. Do not attempt to remove the timiter cap. The
timitercap cannot be removed without breaking the adjusting
needle.
- Be sure you have a clean air filter and the throttle
control cable is adjusted properly (see above).
- Start engine and allowto warm for five minutes. Make
adjustments with engine running and shift!motion control
lever in neutral (N) position.
° idle speed setting - With throttle control lever in slow
(,_) position, engine should idle at 1750 RPM. If
engine idles too slow or fast, turr_ idle speed adjusting
screw in or out until correct idle is attained_
o Idle fuei needle settincl - With throttle control lever in
slow (,_) position, turn idle fuel adjustment needle in
(clockwise) untif engine begins to die and then turn out
(counterclocI_vise) until engine runs rough. Turn needle
to a point midway between those two positions.
ACCELERATION TEST -
- Move throttle control lever from slow (-_) 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..
Nigh 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 OVERSPEEDINGTHEENGINEABOVE
THE FACTORY HIGH SPEED SETTING CAN BE
DANGEROUS.. IF YOU THINK THE ENGINE-GOVERNED
HtGH SPEED NEEDS ADJUSTING, CONTACT YOUR
NEAREST AUTHORIZED SERVICE CENTER/
DEPARTMENT, WHICH HAS PROPER EQUIPMENT AND
EXPERIENCE TO MAKE ANY NECESSARY
ADJUSTMENTS.
CABLE
CLAMP
SCREW,
SPEED
BRACKET
THROTTLE
LEVER
FIG, 32
IDLE SPEED
ADJUSTING
IDLE FUEL /
iADJUSTING
!NEEDLE
FIG. 33
= Recheck idle speed. Readjust ifnecessary.
25