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FUEL SYSTEM
6C-23
SHIFT IDENT.
ASSEM. PLANT CODE
Fig. 6C-38 Carburetor Identification
Alphabetical code letters have been added to all castings
next to the vacuum and air tubes for improved identification
of all hose connections. The code letters are alphabetical and
should be referred to during carburetor installation on the
engine.
The carburetor part number is stamped on the flat
section of the float bowl next to the fuel inlet nut (Fig. 6C-38).
When servicing the carburetor unit, refer to the Adjustment
section for proper procedures and specifications.
Incorporated in the Model 2GC and 2GE carburetor are
six basic systems. They are Float, Idle, Main Metering,
Power, Pump and Choke (Figs. 6C-39 through 6C-50).
CHECK
LARGE INTERNAL
Fig. 6C-39 Float System (Typical)
ELECTRIC CHOKE (FIG. 6C-51)
A ceramic resistor in the electric choke assembly is
heated by electric current and the resistor warms the
thermostatic coil for precise timing of choke valve opening
for good engine warm-up performance.
The electric choke operates as follows:
The electric choke receives electric current operating
through the engine oil pressure switch whenever the engine
is running. The electric current flows to a ceramic resistor
that is divided into separate sections
-
a small center section
for gradual heating of the thermostatic coil, and a large outer
E.G R IEXHAUST GAS
.
E.G.R.TUBE
IDLE NEEDLE
2973
Fig. 6C-40 Idle System
2GE
section for additional rapid heating of the thermostatic coil.
The ceramic resistor functions as follows:
AIR TEMPERATURE BELOW 50°F. (10°C.)
Electric current, applied to the small section of the
ceramic resistor causes the section to heat up and warm the
thermostatic coil which allows gradual opening of the choke
valve for good cold engine warm-up performance. As the
small section of the ceramic resistor continues to produce
heat, a temperature-sensitive bi-metal disk causes a spring
loaded contact to close also applying electric current to the
large section of the ceramic resistor causing the large section
to heat up. Heat from the larger section of the ceramic resistor
increases the rate of heat flow to the thermostatic coil for
more rapid opening of the choke valve.
AIR TEMPERATURE 70°F. (21°C.) A N D ABOVE
Electric current is applied directly to both the small
section, and through the spring contact, to the large section
of the ceramic resistor to provide a rapid heating of the
thermostatic coil for greater choke valve opening when leaner
air/fuel
mixtures
are
desired
at
warmer
ambient
temperatures.
NOTE: Ground contact for the electric choke is
provided by a metal plate located at the rear of the choke
assembly. D O NOT INSTALL A CHOKE COVER
GASKET BETWEEN T H E ELECTRIC CHOKE
ASSEMBLY A N D T H E CHOKE HOUSING.
The electric choke assembly is indexed properly by
aligning the scribe mark on the front cover with the specified
index mark on the choke housing. (See Fig. 6C-51).
The electric choke and thermostatic coil are serviced as
a complete assembly.
DIAGNOSIS
Refer to engine performance diagnosis, Section 6, and/or
cleaning and inspection under unit overhaul in this section.
ON-CAR SERVICE
Carburetor Choke and Hoses
Check choke mechanism and vacuum break for proper
operation at the recommended maintenance intervals. Any
binding condition which may have developed due to
petroleum gum formation on the choke shaft or from damage
should be corrected. Check carburetor choke hoses for proper
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