To Adjust Choke Control; To Adjust Carburetor; Final Setting; Acceleration Test - Craftsman 917.273240 Owner's Manual

Lawn tractor 25.0 hp, 48" mower electric start automatic transmission
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TO ADJUST
CHOKE
CONTROL
The choke control
has been preset
at the
factory
and adjustment
should
not be nec-
essary,
check
adjustment
as described
be-
low before
loosening
cable. If adjustment
is necessary,
proceed
as follows:
1.
With engine
not running,
move choke
Idle Fuel Adjusting
Needle (If Equi
Adjusting
Screw
Control
Cable
Choke
Control
Cable
Stop S_t:ew
Clamp
Screw
control (located on dash panel) to full
choke position.
2. Remove air cleaner cover, filter and
cartridge plate to expose carburetor
choke (See "AIR FILTER" in the Main-
tenance section of this manual).
3. Choke should be closed. If it is not,
loosen casing clamp screw and move
choke cable until choke is completely
closed. Tighten casing clamp screw
securely.
4. Reassemble air cleaner.
Closed For Full
Choke
TO ADJUST CARBURETOR
The carburetor has been present at the
factory and adjustment should not be nec-
essary. However, minor adjustment
may
be required to compensate
for differences
in fuel, temperature,
altitude or load. 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
(counterclockwise)
increases the supply
of fuel to the engine giving a richer fuel/air
mixtu re.
IMPORTANT:
Damage to the needles
and the seats in carburetor may result if
screw is turned in too tight.
PRELIMINARY
SETTING -
1. Be sure you have a clean air filter, and
the throttle control cable is adjusted
properly (see "TO ADJUST THROTTLE
CONTROL CABLE" in the Service and
Adjustments
section of this manual).
2. With engine off turn idle fuel adjust-
ing needle in (clockwise)
closing it
finger tight and then turn out (counter-
clockwise) 1 turn.
FINAL SETTING -
1. Start engine and allow to warm for five
minutes. Make final adjustments
with
engine running and shift/motion control
lever in neutral (N) position.
NOTE: The high idle is set at the factory
and cannot be adjusted.
2. Idle speed setting - With throttle control
lever in slow position, engine should
idle at 1750 RPM If engine idles too
slow or fast, turn idle speed adjusting
screw in or out until correct idle is at-
tained.
3. Idle fuel needle setting - With throttle
control lever in slow position, turn idle
fuel adjusting needle in (clockwise)
until engine speed decreases and then
turn out (counterclockwise)
approxi-
mately 3/4 turn to obtain the best low
speed performance.
4. Recheck idle speed. Readjust if neces-
sary.
ACCELERATION
TEST -
5. Move throttle control lever from slow
to fast position. If engine hesitates or
dies, turn idle fuel adjusting needle out
(counterclockwise)
1/8 turn. Repeat
test and continue to adjust, if neces-
sary, 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 ad-
justing, contact a Sears or other qualified
service center, which has proper equip-
ment and experience to make any neces-
sary adjustments.
26

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