Jeep UNIVERSAL CJ-2A - Page 107

F
FUEL SYSTEM
reservoir through the pump outlet valve. Both
intake and outlet valves are one-way check valves
opened and closed by fuel flow. No mechanical
compoQents are required in the control of valve
operation.
Fuel is delivered to the carburetor only when the
float needle is off its seat. When the fuel level in
the carburetor bowl is high enough for the float to
force the needle against its seat, pressure backs up
to the fuel pump air dome and causes the diaphragm
to stop pumping. In this position, the pump is said
to be balanced because the pressure in the pump-
to-carburetor line equals that of the diaphragm
spring. In this way, fuel from the pump to the
carburetor is always under pressure. The carburetor
uses fuel, causing the float to drop and pull the
carburetor needle valve off its seat. Pressure in the
pump immediately drops as fuel is delivered to the
carburetor reservoir. Almost instantaneously the
diaphragm again starts operating to pump more
fuel. The diaphragm can start and stop many times
in each mile of vehicle· operation, but the pump
actuating linkage is always in operation while the
engine is running. 'I'he fuel pump incorporates a
pulsator and pulsator chamber to dampen the effect
of pump pressure pulsations on the carburetor
needle valve. This prevents high fuel level in the
reservoir that would result from the needle being
jarred away from its seat. Also, operating ecr;momy
105
would be affected because a high fuel level usually
results in an over-rich mixture.
The actuating linkage has its own spring to ensure
continuous contact of the lever to the camshaft
eccentric.
This fuel pump has a sediment bowl and filtering
screen which is attached to the top of the pump by
a wire clamp and thumb nut. The screen and sedi-
ment bowl should be cleaned at least twice yearly
to prevent trouble due to a blocked screen or water
freezing. The bowl should be washed and wiped
dry and the screen dried and then cleaned with a
stiff brush. When reassembling the bowl make cer-
tain that the cork gasket is not broken; reverse it
and position it flat on the seat, then install the
bowl and tighten the thumb nut securely. After
cleaning, start the engine and carefully inspect the
bowl for leakage.
F -40. Disassembly
Remove the cover plate, gasket, and screen or
bowl clamp, sediment bowl, gasket and screen if
so equipped. Mark the two castings with a file to
ensure positioning in the same relation upon
assembly. Remove the screws attaching the fuel
cover to the pump body. Remove the cover,
diaphragm, and spring. Remove rocker arm pin,
FIG. 132-ACCELERATOR
LINKAGE-CJ-3B, CJ-5, CJ-6
1-Grommet
2-Nut and Lockwasher
3--Throttle Control
4-Choke Control
5-Treadle Rod Seal
6-Accelerator Treadle
7-Treadle Hinge Pin
8-Treadle Hinge
9-Nut and Lockwasher
10-Screw
11-Accelerator Rod
12-Nut
13-Adjusting Block
14- Retracting Spring
1 5-Cotter Pin
16- -Lower Bellcrank
17 -Washer
18 · Bellcrank Link Rod
19-Bracket
20-T.,.ottle Wire Stop
21- .oellcrank Spring
22-Rod
~~=Wi.~~ellcrank