To Adjust Carburetor; Preliminary Setting; Final Setting; Acceleration Test - Craftsman 917.270811 Owner's Manual

19.5 hp electric start 42" mower 6 speed transaxle lawn tractor
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belowbeforelooseningcable. If adjust-
mentis necessary, p roceedas follows:
• With engine not running, move choke
control (located on dash panel) to full
choke position.
• Remove air cleaner cover, filter and car-
tridge plate to expose carburetor choke
(see =AIR FILTER" in the Maintenance
section of this manual).
• 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 se-
curely.
• Reassemble
air cleaner.
Choke Closed_
Casing _
_
sCIcreanP_
_
Choke Lever
TO ADJUST
CARBURETOR
The carburetor has been preset at the fac-
tory and adjustment should not be neces-
sary. 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, tuming the mixture screw in
(clockwise) decreases-,the_upply
of fuel to
the engine giving a leaner fuel/air
mixture.
Turning the mixture screw 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 in carburetor may result if screw
is turned in too tight.
PRELIMINARY
SETTING
-
• 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 tum out (countemlockwise)1-1/4
to 1-1/2 turns.
FINAL SE'I-I'ING
-
• Start engine and allow to warm for five
minutes.
Make final adjustments
with
engine running and shift/motion
control
lever in neutral
(N) position.
• With throttle control lever in slow posi-
tion, hold throttle
lever against idle
speed screw and adjust idle speed
screw to obtain 1200 to 1400 RPM.
• While still holding throttle lever against
idle speed screw, tum idle mixture
screw in (clockwise) until engine begins
to die and then tum out (counterclock-
wise) until engine runs rough. Turn
screw to a point midway between those
two positions.
• Continue to hold throttle lever against
idle speed screw and adjust idle speed
screw to obtain 900 to 1200 RPM.
Re-
lease throttle lever.
ACCELERATION
TEST -
• Move throttle control lever from slow to
fast position.
If engine hesitates or dies,
tum idle mixture screw out (counter-
clockwise) 118 tum. Repeat test and
continue to adjust, if necessary, until
engine accelerates
smoothly.
High speed stop is factory adjusted.
Do
not adjust - damage may result.
IMPORTANT:
Never tamper with the
engine govemor, which is factory set for
proper engine speed.
Overspeeding
the
engine above the factory high speed set-
ting 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.
ldle Speed
rew
Idle Mixture
Screw
Throttle Lever
27
Idle Speed
Screw
Throttle
Lever
Mixture
Screw

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