Jeep UNIVERSAL CJ-2A - High-Speed Circuit

'Jeep' UNIVERSAL and 'Jeep' DISPATCHER
F
To properly center the valve in the throat of the
carburetor, the screws should be started in the
shaft, and then with the valve tightly closed (throt-
tle lever adjusting screw backed out) it should be
tapped lightly. This will centralize the valve in the
carburetor throat. Pressure should then be main-
tained with the fingers until the screws are
tightened.
If the carburetor throat is restricted with carbon
deposit it will be necessary to open the throttle
wider than the correct opening to obtain the proper
engine idle speed. Opening the throttle more than
this amount in order to obtain the proper idle will
then uncover more of the slotted idle port than was
intended. This will result in leaving an insufficient
amount of the idle port as a reserve to cover the
period between idle and 20 miles [32 km.] per
hour, where the high speed system begins to cut in.
A
flat spot on acceleration will result. Clean by
scraping with emery cloth.
F-11. High-Speed Circuit
It is rarely necessary to remove the main nozzle
Fig. 116. It can usually be cleaned by removing
the plug and blowing it out with compressed
air. If it is damaged and requires replacing, make
sure, upon installation that only one gasket is
between the nozzle and the seat.
If the carburetor has been in service for a long time
or has been tampered with, it may be found that
the metering rod is improperly adjusted or worn.
A
worn metering rod will have the effect of a rich
mixture above 20 miles per hour [32,2 k.p.h.]. If
the metering rod is worn, the metering rod jet will
also
be worn and both should be replaced. Before
adjusting the metering rod adjust the accelerating
pump stroke, for the pump stroke adjustment will
change the metering rod setting.
To adjust the metering rod, back out throttle lever
adjusting screw "C", Fig. 120, and close the throt-
tle tight. Using gauge T-109-26, Fig. 120, (sup-
plied by Carter Carburetor Co.) loosen nut "B" and
move pin until it seats in the notch of the gauge.
Tighten the nut securely. Remove the gauge and in-
stall metering rod with disc, and connect the spring
through hole in the metering rod.
10451
FIG. l20-METERING ROD GAUGING
To check the setting, note the position of the oper-
ating pin in the eye of the metering rod. It should
just clear within the top of the eye (clearance not
to exceed~"- .397 mm.) when the metering rod
is seated and the throttle stop screw set for proper
engine idle.
F-12. Acclerating Pump Circuit
If the pump plunger is worn, sticks or if the spring
under the leather has lost its tension, replace the
plunger assembly, Fig. 113.
If the pump intake check valve, Fig. 117, leaks
part of the pump discharge will be forced back
throug~ the valve into the float bowl, preventing
a suffic1ent amount of fuel to be discharged from
the jet. If the valve can not be cleaned with com-
pressed air, it must be replaced.
If the pump discharge check valve leaks air will
be drawn into the pump cylinder on the ~p stroke
of the plunger. This gives an insufficient discharge
of fuel into the throat of the carburetor on accelera-
tion causing a flat spot. If the valve can not be
cleaned with compressed air, to prevent leakage
it Il)ust be replaced. '
If the accelerating pump arm spring is weak or
damaged, it will cause poor acceleration.
If the hole in the accelerating pump jet is too
large, the accelerating charge. will be allowed to
pass too fast and will make the mixture too rich.
An enlarged jet must be replaced. A loose jet gives
the same effect. A clogged jet will cause a flat spot
on acceleration.
To adjust the pump stroke, pump gauge T-109-
117C (supplied by Carter Carburetor Co.) should
be used. First back out the throttle adjusting screw
10899
FIG. 121-PUMP TRAV.EL GAUGING
97