Carburetor - Bbd-2 Venturi; Fuel Pump Replacement; Fuel Pump Specifications - Jeep 1979 CJ-5 Technical & Service Manual

FUEL SYSTEMS 1J-9
direct connection test, a vacuum gauge is connected by a
T-fitting into the pump inlet line. This test checks for
obstruction in the fuel line or the in-tank fuel filter.
Direct Connection Test
(1) Disconnect fuel inlet line at fuel pump.
(2) Connect vacuum gauge to fuel pump inlet.
(3) Operate engine at curb idle rpm and note vac-
uum gauge reading. Gauge should indicate a vacuum of
ten inches of mercury (10 Hg) (34 kPa). If the pump
vacuum reading is not within specification, the pump is
defective and should be replaced.
NOTE: Vacuum gauge will not register a reading until
fuel in carburetor float bowl has been used and pump
begins to operate at full capacity.
Indirect Connection Test
(1) Disconnect fuel inlet line at fuel pump.
(2) Install T-fitting between disconnected line and
fuel pump. Attach vacuum gauge to T-fitting.
(3) Operate engine at 1500 rpm for 30 seconds. Vac-
uum should not exceed 2 inches of mercury (7 kPa).
(4) If vacuum exceeds 2 inches of mercury (7 kPa)
check fuel line for blockage. A partially clogged in-tank
fuel filter may also be the cause.
NOTE: Vacuum gauge will not register a reading until
fuel in carburetor float bowl has been used and pump
begins to operate at full capacity.
Fuel Pump Replacement
Removal
(1) Disconnect fuel lines from fuel pump.
(2) Remove retaining screws.
(3) Remove pump and gasket.
Installation
(1) Install pump and replacement gasket.
NOTE: Be sure actuating lever is positioned properly
on camshaft eccentric.
(2) Install retaining screws.
(3) Connect fuel lines to fuel pump.
FUEL ECONOMY TESTS
When checking fuel economy, connect the testing de-
vice between the fuel filter and the carburetor because
of the fuel return system. Do not block off the fuel
return line as this may affect miles-per-gallon reading.
SPECIFICATIONS
Fuel Pump Specifications
Volume
(30 seconds)
Pressure
(PSI)
Vacuum (Hg)
Volume
(30 seconds)
Pressure
(PSI)
Direct Indirect
Six-
Cylinder
1 pint
(.47 liters)
4 to 5
(28 to 34 KPa)
10
(34 KPa)
3
(7 KPa)
Eight-
Cylinder
1 pint
(.47 liters)
5 to 6.5
(34 to 45 KPa)
10
(34 KPa)
3
(7 KPa)
8 0 2 6 2 B
Fuel Tank Capacity
Model Gallons
CJ 14.8 (56.0 liters)
Cherokee
Wagoneer
21.5 (81.4 liters)
Truck 18.2 (68.9 liters)
8 0 7 0 8
CARBURETOR MODEL
B B D - 2
VENTURI
Page Page
Carburetor Circuits 1J-10 Choke Mechanism Service 1J-19
Carburetor Overhaul 1J-12 Service Adjustment Procedures 1J-17
Carburetor Replacement IJ-12 Specifications 1J-19
GENERAL
The Carter Model BBD two-venturi carburetor in-
corporates three lightweight aluminum assemblies, the
air horn, main body and throttle body (fig. 1J-15).
The air horn contains the choke valve assembly, me-
chanical linkage for accelerator pump and metering
rods, and bowl vent.
The main body contains fuel bowl, acccelerator pump,
vacuum piston and metering rod assembly, venturi as-
sembly and solenoid, if equipped.