Carburetor Circuits; Float Circuit; Idle Circuit - Jeep J-10 Series 1982 Technical & Service Manual

Identification
The carburetor model identification is stamped verti
cally on the float bowl in a flat area adjacent to the
vacuum tube (fig. 1J-19). When replacing the float bowl,
follow the manufacturer's instructions contained in the
service package and ensure that the identification num
ber is transferred to the new float bowl.
Refer to the part number on the bowl when servicing
the carburetor.
90648
Fig. 1J-19 Model 2SE Carburetor Identification
CARBURETOR CIRCUITS
Model 2SE carburetor has six basic circuits. They are:
• Float
•Idle
• Main Metering
• Power Enrichment
•Pump
• Choke
Float Circuit
The float chamber is located adjacent to the primary
and secondary bores (figs. 1J-20 and 1J-21). This feature
assures adequate fuel supply to both carburetor venturi
bores during all standard engine operations.
INTERNAL
VENT SCREEN
FLOAT
HINGE
PIN
PLASTIC
INSERT
GASKET
FUEL FILTER
PULL CLIP
VENT TUBE
TO CANISTER
FLOAT VALVE
FLOAT VALVE SEAT
fTL VALVE SEAT GASKET
90649
Fig. 1J-20 Model 2SE Carburetor-Float Circuit
FUEL RESERVOIR
FLOAT AND
LEVER ASSEMBLY
SECONDARY BORE
FUEL SYSTEMS 1J-13
PLASTIC FILLER
BLOCK
PRIMARY BORE
90650
Fig. 1J-21 Model 2SE Carburetor—Fuel Reservoir
A single pontoon float, brass needle seat, and a rubber
tipped float needle with pull clip are used to control the
fuel level in the float chamber. The float chamber is
internally vented through a vertical vent cavity in the
air horn. Above this vent cavity is a removable vent
stack assembly that has a small meshed screen at its
top. This vent stack provides the correct height for the
internal vent.
The float chamber is also externally vented through a
tube (fig. 1J-18) in the air horn. A hose connects this
tube directly to a vacuum operated vapor vent valve
located at the vapor canister. When the engine is not
operating, the canister vapor vent valve is open, allow
ing fuel vapor from the float chamber to flow into the
canister where it is stored until purged. The venting of
fuel vapor from the carburetor float bowl to the canister
conforms to evaporative emission requirements and im
proves hot engine starting.
Idle Circuit
Fuel for engine idle and partial throttle operation is
controlled by the idle circuit. Fuel flows through the
main metering jet into the idle tube and continues to and
through the idle cross-over passage where it is mixed
with air entering from the lower idle air bleed (fig.
1J-22).
A partial throttle adjustment screw in the float bowl
aids in refinement of the fuel mixture for good emission
control. This screw is preset during factory assembly
and a plug is installed to prevent indiscriminate tamper
ing and to seal against any fuel leaks. The plug should
not be removed nor the screw adjusted during normal
service. If it becomes necessary to replace the float bowl,
the new service float bowl will include an adjustable
partial throttle (APT) screw that has been preset and
plugged as required.