Idle Metering (Low Speed) Circuit; Bowl Vent - Jeep J-10 Series 1982 Technical & Service Manual

1J-60 FUEL SYSTEMS
The float circuit maintains the correct fuel level in the
bowl. This enables the fuel metering circuits to deliver
the proper air/fuel mixture to the combustion cham
bers. The amount of fuel entering the bowl is regulated
by the distance the fuel inlet needle is raised off its seat.
The float drops as the fuel level drops and allows the
fuel inlet needle to move off its seat. This permits addi
tional fuel to enter the bowl. When the fuel reaches the
preset level, the fuel inlet needle is lowered and admits
only enough fuel to replace that being used.
NEEDLE
AND
SEAT
ASSEMBLY
FUEL
INLET
Bowl Vent
Rg. 14-116 Float Circuit
FUEL
BOWL 80004
Two bowl vents are required. The internal vent is used
to balance air pressure in the fuel bowl when the engine
is operating. The external vent provides a method of
controlling fuel vapor in the bowl when the engine is not
operating.
The external fuel bowl vent permits vapor to move
from the carburetor to the fuel vapor storagecanister. A
bell crank attached to the accelerator pump housing
actuates the bowl vent (fig. U-l 17). At idle or solenoid
Off position (if equipped), the vent opens, permitting
vapor to pass. At any throttle position above idle, the
vent is mechanically closed.
Idle Metering (Low Speed) Circuit
Fuel for idle and low speed operation flows from the
fuel bowl through the main jets into the main wells.
From the main wells, the fuel is metered as it passes
through calibrated restrictions at the lower end of the
idle tubes. After flowing through the idle tubes, the fuel
enters diagonal passages above the tubes. The fuel is
metered again as it flows downward through restric
tions at the lower end of the diagonal passagesand then
enters the idle passages in the main body (fig. 1J-118).
PLUNGER VENTTO
IN VENTED CANISTER
POSITION
BELLCRANK
THROTTLE LEVER
IN CLOSED POSITION
Fig. 14-117 External Bowl Vent
IDLE
MIXTURE
SCREW
PORT
>N ANTI-SIPHON
AIR BLEED
RESTRICTOR CAP
80269
80005
Fig. 14-116 Idle Metering Circuit
Air enters the idle circuit through air inlets that are
located in the main body directly below the booster
Y
$3^
/Hi