Idle Speed/Throttle Actuator - Mechanical: Description and Operation

Throttle Control System:

The carburetor mounted throttle controller serves as both a engine cranking throttle opener and as a dashpot. The vacuum supply line has a check valve with a small metered orifice. During rapid deceleration, i.e. high vacuum conditions, it slows throttle closing, reducing emissions. During engine, starting when the vacuum signal is not strong enough to overcome spring pressure. The throttle valve is then forced open slightly to improve engine starting.