Carburetor – Cub Cadet LT1040 User Manual

Page 23

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23

Deck Wheels

Each of the tractor deck’s front gauge wheels is
equipped with a grease fitting. Lubricate with a No. 2
multi-purpose grease applied with a grease gun after
every 25 hours of tractor operation.

Carburetor

NOTE:

Carburetor adjustments should be made only

after the engine has warmed up.

The engines on Cub Cadet Series 1000 tractors are
equipped with a fixed main jet carburetor.

Carburetors are equipped with a idle speed adjustment
screw and a low idle fuel mixture screw.

The carburetor is designed to deliver the correct fuel-to-
air mixture to the engine under all operating conditions.
The main fuel jet is calibrated at the factory and is not
adjustable. The low idle fuel mixture screw is also set at
the factory and normally does not need adjustment.

If the engine is hard to start, runs roughly, or stalls at
low idle speed, it may be necessary to adjust or service
the carburetor.

Turning the low idle mixture screw in (clockwise)
decreases the supply of fuel to the carburetor. This
gives a leaner fuel-to-air mixture. Turning the mixture
screw out (counterclockwise) increases the supply of
fuel to the carburetor. This gives a richer fuel-to-air
mixture. Setting the screw midway between the lean
and rich position will usually give the best results.

Figure 15

Troubleshooting

If engine troubles are experienced that appear to be
fuel system related, check the following areas before
adjusting the carburetor.

Make sure the fuel tank is filled with clean, fresh
gasoline.

Make sure the fuel tank cap vent is not blocked and
that it is operating properly.

Figure 16

If the fuel tank is equipped with a shut-off valve,
make sure it is open.

Make sure that the in-line fuel filter is clean and
unobstructed. Replace the filter if necessary.

Make sure fuel is reaching the carburetor. Check
the fuel lines and fuel pump for restrictions or faulty
components, replace as necessary.

Make sure the air cleaner element is clean and all
air cleaner element components are secure.

If, after checking the items listed above, the engine is
hard to start, runs roughly, or stalls at low idle speed, it
may be necessary to adjust or service the carburetor.

Adjustment

NOTE:

Engines may have a fixed idle or limiter cap on

the idle fuel adjusting screw. Step 2 can only be
performed within the limits allowed by the cap.

1.

Start the engine and run at half throttle for five to 10
minutes to warm up. The engine must be warm
before performing steps 2 and 3.

2.

Low Idle Fuel Screw Setting: Place the throttle
into the “idle” or “slow” position. Turn the low idle
fuel mixture screw out (counterclockwise) from the
preliminary setting until engine speed decreases
(rich). Note the position of the screw. Now turn the
mixture screw in (clockwise). The engine speed
may increase, then it will decrease as the screw is
turned in (lean). Note the position of the screw. Set
the adjusting screw midway between the rich and
lean settings. See Figure 16.

3.

Low Idle Speed Setting: Place the throttle control
into the “idle” or “slow” position. Set the low idle
speed to 2150 RPM* by turning the low idle speed
adjusting screw in or out. Check the speed using a
tachometer.

Low Idle

Mixture Screw

Idle Speed

Adjustment Screw

Lean

Rich

Adjust to Midpoint

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