Jeep UNIVERSAL CJ-2A - Choke Circuit

F
FUEL SYSTEM
Pump action is prolonged by the pump arm spring
because the hole in the pump jet restricts the flow
of fuel while it is being forced out by the pump.
The prolonging of the pump discharge gives the
fuel in the high speed circuit sufficient time to
flow fast enough to satisfy the demands of the
engine.
As the accelerator pedal is allowed to return to its
original position, the pump plunger is lifted up-
ward. This creates a reduced pressure in the pump
cylinder which opens intake ball check valve and
closes discharge ball check valve thereby drawing
in a new charge of fuel from the bowl.
FIG. 118-CHOKE CIRCUIT
37-Choke Valve
38-Screw
39-Choke Shaft and Lever Assembly
.40-Choke Oporating Lever and Spring
F-7. Choke Circuit
This circuit, Fig. 118, is used only in starting and
warming up the engine, by restricting the amount
of air allowed to enter the carburetor thereby pro-
ducing a richer mixture. It consists of a choke shaft
and lever assembly choke operating lever and
spring choke valve and screws.
F-8. SERVICING AND ADJUSTMENT
F -9. Float Circuit
If the float is loaded with fuel or if the holes for the
pins are worn, the carburetor will flood. Poor ac-
tion of the float needle will occur if the lip of the
float bracket is worn. In this event, it shoulc:f be
smoothed with emery cloth.
The needle and seat may leak because of wear,
damage or sticking and will cause the carburetor
to flood. Needles and seats are available only in
matched sets. Never replace the needle without
replacing the seat.
96
To determine the float level, Fig. 119, first turn the
bowl cover gasket around and with the cover in
position as shown, the float by its own weight
should rest at %" [9,525 mm.] (as indicated by
the gauge).
To change the float level press down with a screw
driver on the brass lip of the float, holding up on
the float while assembled to the cover of the car-
buretor. Bending the lip in this way allows it to
retain its curvature which is necessary for the
correct operation of the float valve.
Be sure the spring and pin in the valve are in posi-
tion and that the spring has not been stretched.
F-10. Low-Speed Circuit
In the low speed circuit, Fig. 115, it will be found
that the fuel does not come through the main
metering jet, but through the idle well jet, and
the low speed jet the openings of which are care-
fully calibrated. If they are damaged they should
be replaced. The jets should always be tightly
seated. The by-pass and air bleed holes must be
clear. Carbon deposits which may form in the
throat of the carburetor might restrict the air
bleed holes to the extent that insufficient air will
be supplied to mix the fuel before it reaches the
idle port.
This
condition will usually be indicated if it is
necessary to screw the idle mixture adjusting screw,
in closer than the minimum limit of Y2 turn.
If the condition is bad, a rolling idle may continue
even after the idle mixture adjusting screw is
screwed entirely in against the seat. The air bleed
holes may be cleaned with a soft copper wire.
The idle port must be kept clean and unrestricted.
If it is damaged the engine will not perform
properly at low speeds and a new body flange will
be required.
A letter "C" enclosed by a circle is stamped on the
face of the throttle valve. When the valve is in-
stalled in the carburetor, this side should be toward
the idle port, and facing the intake manifold as
viewed from the bottom.
FIG. 119-FLOAT LEVEL SETTING