Craftsman 917254791 38" 12.5-hp riding lawn tractor

User Manual - Page 24

For 917254791.

PDF File Manual, 52 pages, Download pdf file

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SERVICE AND ADJUSTMENTS
ENGINE
TO ADJUST THROTTLE CONTROL CABLE
(See Fig. 34)
The throttle controJ has been preset at the factory and
adjustment should not be necessary. Check adjuslment as
described below before loosening cable tf adjustment is
necessary, proceed as follows:
With engine no!, running, move throttle oontroE lever
from SLOW to CHOKE position Slow[ymavelever
from "CHOKE" to "FAST" position
, Check that hole inthrottle lever and hole In plate line up.
If holes "A" are not a_lgned, loosen clamp screw and
move throtlte cable until holes are aligned, Tighten
clamp screw securely
TO ADJUST CARBURETOR (See F|g. 34)
The carburetor has been preset at the factory and adjust.,
ment should not be necessary,, However, minor adjust*
ment may be req uired to compensate for differences Infuel,
temperature, altitude or load, If the carburetor does need
adjustment, proceed as felfows:
in general, turning the mixture screws In (clockwise) de-
creases the supply of fuel to the engine giving aleaner lust/
air mixture, Turning the mixture screws out (counter-
clockwise) increases the supply of fuel to the engine giving
a richer lust/air mixture
IMPORTANT; DAMAGE TO THE NEEDLES AND THE
SEATS IN CARBU RETOR MAY RESULT
IF SCREWS ARE TURNED iN TOO
TIGHT
PRELIMINARY SETTING -
Be sure you have a clean air filter and the throttle
control cable is adjusted propedy (see above)
With engine off turn high speed mixture screw in
(clockwise) c_oslng it finger tight and then turn out
(counterclockwise) f -112 turns,
Turn idle mixture screw in (clockwise) closing finger
tight and then turn out (counterclockwise) 1 turn.
FINAL SETTING -
Start engine and allow to warm for five minutes. Make
final adjustments with engine running and shift/motion
control lever in "NEUTRAL" position_
With throttle control tever in "FAST" position, turn high
speed mixture screw In (clockwise) unti! engine begins
to die then turn out (counterclockwise) untll engine runs
rough. Turn screw to a point midway between those
two positions,
With throttle control lever in "SLOW" position, turn idle
mixture screw in (clockwise) unfit engine begins todie
and then turn out (counterclockwise) until engine runs
rough. Turn screw to a point midway between those
two positions
With throttte control lever in "SLOW" position, engine
shouldidle at 2100 RPM Ifengtne idles too slow, move
throttle control lever above Idle end turn Idle speed
screwfn (clockwise) oneturn. Setthrotttecontrollever
at "SLOW", Repeat until satisfactory idle is altained_
If engine idles too fast in "SLOW" position move throttle
control lever above idle and turn idle speed screw out
(counterclockwise) one turn, Set throttle control lever
at "SLOW" Repeat untO!satisfactory idle is attained.
ACCELERATION TEST -
Move throttle control lever from "SLOW" to "FAST"
position. If engine hesitates or dies, turn high speed
mixture screw out (counIarclockwtse) 1/8 turn. Repeat
lest and continue to adjust, if necessary, unlit 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, OVER-
SPEEDING 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, WHICH HAS PROPER
EQUIPMENT AND EXPERIENCE TO
MAKE ANY NECESSARY ADJUST.,
MENTS.
THROTTLE CABLE CLAMP SCREW
LEVER
24
iDLE
MIXTURE
SCRE3N
HIGH SPEED
MIXTURE
SCREW
FIG_34
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