The Accelerated Idle System consists of the following components:
- Centrifugal Governor attached to the air filter and driven by the speedometer cable.
- Solenoid Valve mounted onto the air filter support.
- Throttle Plate Opener connected through a linkage to the throttle plate (primary) of the carburetor.
When the speed of the vehicle is greater than 21 MPH (34 Km/H), the contact points in the centrifugal governor close, activating the solenoid valve. The solenoid valve opens the control valve to the vacuum chamber which is connected via a pipe to the intake manifold. During this acceleration, the vacuum pressure is too low to move the spring loaded diaphragm.On Deceleration
During deceleration the carburetor throttle plate closes. The vacuum pressure in the intake manifold rises, and the spring loaded diaphragm closes, moving the attached rod. This in turn partially opens the first barrel carburetor throttle plate via linkage.
This is the fast idling position. When the vehicle speed is less than 17 MPH (27 Km/H), the centrifugal contacts are open and the solenoid valve is no longer activated. The vacuum supply is then shut off to the spring loaded diaphragm, and it returns to its initial position.