To adjust carburetor {see fig. 28), Service and adjustments – Craftsman 917.25650 User Manual
Page 25
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SERVICE AND ADJUSTMENTS
TO ADJUST CARBURETOR {See Fig.
28
)
The carburetor has been preset at the factory and adjust
ment should not be necessary. However, minor adjust
ment may be required to compensate fordifferences in fue!,
temperature, altitude or load. If the carburetor does need
adjustment, proceed as follows:
In general, turning idle mixture valve
in
(clockwise) de
creases the supply of fuel to the engine giving a leaner fuel/
air mixture. Turning the idle mixture valve
out
(counter
clockwise) increases the supply of fuel to the engine giving
a richer fuel/air mixture.
IMPORTANT:
DAMAGE
TO
THE
NEEDLE
VALVE
AND
THE SEAT IN CARBURETOR MAY RESULT IF SCREW IS
TURNED IN TOO TIGHT
PRELIMINARY SETTING -
» Air cleaner assembly must be assembled to the carbu
retor when making carburetor adjustments.
® Be sure the throttle control cable is adjusted properly
(see above).
» With engine off turn idle mixture valve
in
(clockwise)
closing it finger tight and then turn
out
(counterclock
wise) 1 full turn
FINAL SETTING -
•
Start engine and aflow to warm for five minutes. Make
final adjustments with engine running and shift/motion
control lever in neutrai (N) position,
» Move throttle control lever to slow
( - m )
position. With
finger, rotate and hold throttfe fever against idle speed
screw. Turn idle speed screw to attain 1750 RPM.
» While still holding throttle lever against idle speed
screw, turn idle mixture valve
in
(clockwise) until en
gine begins to die and then turn
out
(counterclockwise)
until engine runs rough. Turn valve to a point midway
between those two positions. Release throttle lever.
ACCELERATION TEST -
• Move throttle control lever from slow (•») to fast (•%?)
position. If engine hesitates or dies, turn idle mixture
valve
out
(counterclockwise) 1/8turn. Repeattestand
continue to adjust, if necessary, until engine acceler
ates 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,
FiG. 28
25