Lesson 3/Learning Event 1
Repair or replace any part which is damaged or shows excessive wear.
To replace the carburetor and throttle control, perform the following steps.
Spread the control rod clevis and install the throttle lever.
When installing the throttle lever, be sure the punch mark is pointed up and
Step 2. Install the new gaskets and rear cover to the throttle housing. Install the throttle
housing to the carburetor.
Step 3. Using a new gasket, install the carburetor onto the intake manifold. Using an inch-
pound torque wrench, torque the carburetor mounting nuts to the intake manifold to 60-85 in. lbs.
(10716-15181 gr. cm).
Install the air cleaner elbow duct to the carburetor.
Install the fuel line to the carburetor.
Reconnect the throttle lever to the shaft.
Install the front throttle housing gasket and the housing.
The adjustment of the carburetor can be completed by performing the following steps. Figure 16
on page 44 can be used as a guide for adjusting the carburetor.
Step 1. With the engine stopped, turn the main adjustment needle and the idle adjustment
needle fully clockwise to close.
Step 2. Turn
adjustment needle three-quarters
of a turn counterclockwise, and the idle
adjustment needle one-half turn counterclockwise. Start the engine and run until warm.
Step 3. Observe the engine exhaust
. If the exhaust
is black, close
If the engine misfires or seems low in power, open the main adjustment needle. Adjust the main
adjustment needle until the engine delivers maximum power with a minimum of exhaust smoke.
Regulate the idle mixture in a similar manner.
Step 5. Regulate the engine idle R.P.M. by turning the idle speed regulating screw clockwise or
counterclockwise enough to keep the engine running smoothly.