1948-1952 Shop Service Manual - - Hudson-Essex-Terraplane Club

4 - 4 FUEL SYSTEM & EXHAUST
against an adjusting screw when the choke is closed. The
screw is adjusted to hold the throttle open sufficiently to
provide necessary engine speed (fast idle) during the warmup
period. As the choke valve opens, the fast idle cam
moves away from the screw allowing the engine to run at
normal idle speed.
An unloader is provided in the choke linkage to open the
choke valve when the accelerator pedal is fully depressed.
This allows the engine to clear itself of excess fuel if the
engine is flooded during the starting period.
ANTI-PERCOLATOR VALVE:
When the car stands in extremely hot weather or after a
hard run, fuel in the carburetor bowl may vaporize and set
up pressure in the bowl. To prevent this pressure forcing the
fuel out the high speed nozzle (percolating), an anti-percolator
device vents the carburetor bowl to the atmosphere
when the throttle is closed, relieving the pressure in the
bowl.
FIGURE 1
CLIMATIC CONTROL (CHOKE):
All model WA-1 Carburetors are equipped with Carter
Climatic Control, Figure 1, which serves as an automatic
choke. The Climatic Control closes the choke valve when
the engine is cold. The Climatic Control is connected to the
exhaust manifold by a tube (I) which allows exhaust gases
to enter through the opening into the control housing and
warm the thermostatic spring (C) and decreases the spring
tension. A vacuum piston (D) is connected to the choke
valve and operates from the vacuum of the intake manifold.
The pull of the piston against the thermostatic spring opens
the choke valve (H) as the engine becomes warm.
To prevent the thermostatic spring (C) from closing the
choke valve if the throttle is opened on a cold engine, a
lockout is provided in the choke linkage to hold the choke
open on all wide open throttle operations.
A cam on the choke valve shaft is brought
FIGURE 2
COPYRIGHT 1950 BY CARTER CARBURETOR CORPORATION. ALL RIGHTS RESERVED.