AISAN 2-Barrel -- TOYOTA 22R Engine: Description

Carburetor is a 2-barrel downdraft design with primary and secondary venturi. An automatic choke containing a bimetal spring heated by coolant provides proper air/fuel mixture control during engine warm-up. Secondary throttle valve is actuated by a vacuum diaphragm unit with a kick-up (open) lever. Secondary valve begins to open when primary throttle valve opening exceeds 50°.

A thermostatic valve provides air flow under secondary throttle valve when ambient air temperature is high to maintain proper combustion. Other features include a choke opener, an auxiliary accelerator pump, a secondary slow circuit fuel cut system, a fast idle cam breaker, a deceleration fuel cut system, and a solenoid valve.