each end to permit solid
seating against the wall
of the air horn.
Due to the
choke valve seating against the walls of the air horn, it cannot be
damaged by backfire. The choke lever
is mounted on a boss on the air horn and is retained by a snap ring fitted
into a groove in the
lever floats on the shaft and is connected to it through a light coil spring.
This spring hooks to the choke
lever and to the choke shaft. In this way the choke valve is operated by
the choke lever through the spring.
choke button on the instrument panel is pulled out, the light valve spring causes
the valve to follow the movement of the lever, closing the choke valve. As the engine starts, the rush
of incoming air through
the air horn of the carburetor overcomes the tension of this spring and
the valve automatically assumes
the correct position to provide the proper amount of air for the
mixture to enter and prevent
accelerating pump consists of a cylinder with a plunger containing an air bell and
two check valves, one on the
inlet and one on the outlet side. The accelerating pump plunger
including the shaft, guide and
leather is made as an assembly. The shaft is rectangular and bears in the
bowl cover. The inlet check valve has a bakelite disc while the outlet check valve has a brass
disc. The brass disc aids fuel economy since its weight tends to keep it on its scat and prevent lifting
from the seat due to the air
velocity in the carburetor.
movement of the pump plunger, when the
throttle is closed, draws a small metered quantity of gasoline into the bottom of the
cylinder. The slightest opening of the throttle
(downward movement of the
plunger) causes an immediate discharge through the pump jet
pointing downward into the main
venturi. This action is illustrated in Fig. 73.
enters the low speed jet through a 3/64" hole drilled through the jet at the recess
between the threaded
section and the base of the jet. which coincides with the low speed well in
the carburetor body, Fig. 71.
The metering hole is drilled
vertically and is .035" in diameter. This design prevents the possibility of the
engine stalling due to
gasoline surging away from this jet when the brakes are applied
nozzle is of two-piece construction with the inner nozzle pressed into the outer
nozzle, thereby maintaining
the proper relationship between the openings in the walls of the two
nozzles. The nozzle assembly is held in place by a brass plug
having a 1/8" hole drilled through its