Figure 57. Adjusting Governor Using Tool SE-2072-2
Governor Valve Body
8. Reinstall governor clamp and gasket assembly.
9. Reinstall governor seal.
10. On distributors so equipped, be sure the governor spinner
valve air cleaner is cleaned or replaced at regular intervals
depending on severity of operation.
The automatic choke assembly consists of a
bimetallic thermostat spring and vacuum piston. The
automatic choke assembly is mounted on the carburetor main
body. A passage through the main body connects the
vacuum system to the manifold area. When the engine is
cold, the bimetal spring closes the choke plate for starting.
When the engine starts, manifold vacuum is applied to the
choke piston through a passage in the main body and with the
help of air flow on the offset choke plate, opens the choke
against the tension of the bimetal spring.
A heat stove is installed in the exhaust manifold and
an asbestos-covered tube connects the heat stove to the
choke housing. As the engine is warmed up, hot air is
circulated to the choke housing to warm up the bimetal spring.
As the spring warms up, its tension will be released on the
choke shaft and allow it to open gradually. The warm air then
passes through a hole in the choke piston and down the
passage in the main body to the manifold vacuum passage.
A choke lever is provided on the side of the carburetor which
actuates a fast idle cam during choking. The fast idle cam
has a series of stops on one side which are designed to
increase the engine idle RPM for smoother running when the
Figure 58. Automatic Choke Assembly
1. Piston and Lever
5. Vacuum Passage
6. From Heat Tube
2. Choke Housing
7. Vacuum Passage
3. Choke Housing Plate
4. Thermostat Spring
engine is cold. As the engine is warmed up and the choke opens,
each step on the fast idle cam permits the engine to run at a
An adjustable piston stop screw controls the initial travel
of the choke piston. The piston, in turn, controls the initial opening
of the choke plate or choke qualifying dimensions. To check the
choke qualifying dimension, follow the procedure outlined below:
Bend a paper clip as shown in insert in Fig. 59).
Place bent end of clip on top of piston and depress
piston until it bottoms on stop screw (Fig. 59).
Rotate choke lever tang counterclockwise until
choke piston link touches top of piston (Fig. 59).
Measure clearance on lower edge of choke plate at
inner wall of air horn. See SPECIFICATIONS for
Adjust clearance by moving adjusting screw in or
After adjustment has been established, seal off
head of adjusting screw with sealing compound.
A small unloader lever is provided on the throttle shaft
which will manually open the choke plate when the throttle lever is
at the wide open position. This permits the operator to relieve an
CGES-125-T Page 39
PRINTED IN UNITED STATES OF AMERICA
ENGINE DIVISION SERVICE MANUAL