To Adjust Carburetor; Acceleration Test - Craftsman 917.28803 Operator's Manual

Lawn tractor 17.5 hp, 42" mower electric start 6 speed transaxle
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2.
Check
that holes '_'
in governor
control
lever
and
hole
in governor
plate
line-
up.
If holes
'_' are not aligned,
loosen
clamp screw and move throttle
cable until
holes
are aligned.
Tighten
clamp
screw
securely.
Governor Control Lever
Governor
Plate
Clamp
Screw
TO ADJUST
CARBURETOR
Cable
NOTE:
The
carburetor
on this
engine
is
low emission.
It is equipped
with
an idle
fuel
adjusting
needle
with
a limiter
cap,
which
allows
some
adjustment
within
the
limits
allowed
by the cap.
Do not attempt
to remove
the limiter
cap.
The
limiter
cap
cannot
be removed
without
breaking
the
adjusting
needle.
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,
turning
idle
mixture
valve
in
(clockwise)
decreases
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
-
1.
Air cleaner
assembly
must be assembled
to the carburetor
when making carburetor
adjustments.
2.
Be sure the throttle
control
cable
is ad-
justed
properly
(see above).
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.
2.
Move throttle
control
lever to slow posi-
tion. With finger,
rotate
and hold throttle
lever
against
idle speed
screw. Turn idle
speed
screw
to attain
1750
RPM.
3.
While
still holding
throttle
lever
against
idle
speed
screw,
turn
idle
mixture
valve
full travel
clockwise
then
counter-
clockwise
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 (coun-
terclockwise)
1/8 turn.
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
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
a Sears
or other
qualified
service
center,
which
has
proper
equipment
and experience
to make
any necessary
adjustments.
Idle Speed
Throttle
With Limiter
26

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