22
CARBURETOR ADJUSTMENTS
WARNING
When making adjustments to the carburetor
while the engine is running, disengage the PTO
clutch and engage the brake pedal lock. Keep
clear of all moving parts and be careful of all hot
surfaces. Carbon monoxide fumes can be fatal!
Do not make any adjustments to the carburetor
in a confined area such as a storage building.
Move the tractor outside into the air.
The engine is equipped with a certified fixed
carburetor. The high idle is set at the factory and
cannot be adjusted. The low idle needle is factory
preset and either fixed or equipped with a limiter cap
which should not be readjusted.
If the engine does not operate properly and the
problem appears to be fuel system related, check the
following areas before adjusting the carburetor: Refer
to MAINTENANCE section.
•
Check for fuel in fuel tank
•
Check fuel cap vent for blockage
•
Check fuel line for pinched or obstructed areas
•
Check for fuel filter blockage
•
Check for a clogged air filter
If all of the above checks are okay and the engine
continues to operate poorly, contact your Cub Cadet
dealer.
Adjusting the Idle Speed.
If the engine stalls at low idle speed or idles roughly, it
may be necessary to adjust the idle speed.
•
Start the engine and run at half throttle for 5 to
10 minutes to warm up. The engine must be
warm before making adjustments. Check that
the throttle and choke plates can fully open.
•
Idle Speed Setting: Place the throttle control
into the “idle” or “slow” position. Set the low idle
speed to 1200 rpm (± 75 rpm) by turning the
low idle speed adjusting screw in or out. Check
the speed using a tachometer (See Figure 17).
Figure 17
LOW IDLE SPEED
ADJUSTMENT SCREW
Summary of Contents for LT 2138
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