(19) Clean all metal parts and thoroughly dry with
compressed air prior to reassembly.
12-3. Inspecting and Reassembling the Carburetor.
a. Throttle Body.
(1) Check the throttle shaft for excessive wear in the
throttle body. If the wear is extreme, replace the throttle
(2) Install the idle mixture screw and spring in the
body. Make sure that the tapered portion is straight and
smooth. If it is grooved or ridged, install a new idle mixture
screw to insure having correct idle mixture control.
(3) Turn the screws lightly until they seat; then back
out 1-1/2 turns.
b. Main Body.
(1) Place the insulator in position. Aline the throttle
body with the main body and install and tighten the screws
(2) Install the accelerator pump discharge check balls
Figure 12-10. Testing the Accelerator Pump
Intake and Discharge.
(b) Using a small clean brass rod, hold the
discharge check ball down firmly on its seat. Again raise
the plunger and press downward. You should not see any
fuel coming from the intake or the discharge passage
(c) If fuel is discharged, it means there is dirt in
the system or there is a damaged check bail or seat. Clean
the passage again and repeat the test.
(d) If there is still leakage, stake the check ball
seats by placing a piece of drill rod on top of the check ball
and lightly tapping it with a hammer. This will form a new
seat. Remove the leaked fuel from the bowl through the
inlet check ball located at the bottom of the plunger.
(e) Install the discharge check ball. Put new
gaskets on the venturi cluster and install the cluster in
the cluster screws securely.
c. Checking the Float Setting. The carburetors are
equipped with a rubber-tipped fuel inlet needle. The needle
tip is a rubber material which is not affected by gasoline and
is stable over a wide range of temperatures. It is flexible
enough to make a good seal on the needle seat, and to give
Figure 12-9. Installing the Accelerator Pump Intake and
do as follows:
Discharge Check Balls.
(1) Install the floats with a fulcrum pin and pin the
(3) Drop the accelerator pump intake check ball into
retainer in the main body.
the bottom of the pump cylinder.
(2) Install the needle, seat, and gasket in the body.
(4) Check the accelerator pump system and the fuel
Tighten them securely.
inlet and discharge ball check valves as follows:
(3) Turn the main body over, catching the pump
(a) Pour clean gasoline into the carburetor bowl,
intake check ball, so that only the weight of the floats is
approximately l/2-inch deep. Slide the pump plunger into
forcing the needle against the seat. Hold your finger
the cylinder. Raise the plunger and press lightly on the
against the retainer to fully seat the fulcrum pin.
shaft to expel the air from the pump passage.