Air Valve and Vacuum Break Adjustment (Varajet)
Secondary Metering Circuit (Varajet)
Unloader and Lockout (Varajet)
Accelerator Pump Circuit (Varajet)
Main Metering Circuit (Varajet)
The Rochester Varajet II is a two stage carburetor of down draft design for the 4 cylinder 2.5 litre Chevrolet passenger car, Oldsmobile, and Pontiac engine (except California). To reduce carburetor weight, aluminum die castings are used for the air horn, float bowl, and throttle body except that a zinc die cast choke housing is used to reduce heat transfer for good engine warm-up operation. A heat insulator gasket is used between the throttle body and float bowl to reduce heat transfer to the float bowl.
The primary side of the Model 2SE is comprised of six systems; float, idle, main metering, power, pump, and choke. The secondary side has one metering system which supplements the primary main metering sytsem and receives its fuel from the common float chamber.
The primary stage uses a triple venturi, with a small 35mm bore that results in good fuel control during idle and part throttle operation.
The secondary stage has a large 46mm bore that provides sufficient air capacity for engine power requirements. An air valve is used in the secondary stage with a single tapered metering rod.
The choke system consists of the choke housing and electrically operated thermostatic coil mounted on the float bowl and throttle body. The thermostatic coil is calibrated to provide the correct air/fuel mixtures for good cold engine started and, partially open, running during the warm-up period.
There is a separate screw located in the primary throttle lever for fast idle speed adjustment. A screw, located in the throttle body, is used to make the curb or base idle speed setting (solenoid de-energized).
An exhaust gas recirculation system (EGR) is used on all applications to control oxides of nitrogen. The vacuum supply port necessary to operate the recirculation valve is located in the throttle body and connects through a channel to a tube in the float bowl. This tube is connected by a hose to the EGR valve.
An idle speed solenoid is used to position the primary throttle valve to obtain idle speed requirements of the engine.
The Varajet II carburetor is also used on 1979 Chevrolet and GMC Light Duty Trucks using the 4.1 lite 6 cylinder engine.
This application includes those design features described above except for feature differences required for the 6 cylinder engine such as a secondary side vacuum break with bracket mounted idle speed solenoid, aluminum choke housing die cast material, and calibration.
To properly identy your Varajet and select the correct rebuild kit, look for the carburetor number stamped into the side of the bowl as illustrated below:
