Carburetor - Carter BBD 2-Bbl: Description

The Carter model BBD is a 2-barrel downdraft carburetor. The BBD has 4 basic fuel metering systems: float (fuel inlet) system; idle (low speed) system; accelerator pump system; and the main (high speed) system.

The float system maintains fuel level. The idle system is used for idle and initial part-throttle operation. The main system is used for part-throttle and cruising operation. The pump system provides additional fuel for acceleration.

An electric choke with a choke diaphragm is used. The carburetor is equipped with a stepper motor to control air flow in metered air bleeds in the main fuel metering circuit. All Jeep vehicles use a vacuum solenoid called a Solevac to keep idle speed constant when load is placed on engine.