Choke Opener System: Operation

The cranking leak system bleeds vacuum from the choke opener during cranking. During cold engine starts and when engine is running, the cranking leak solenoid is de-energized. When cranking leak system is de-energized, solenoid is closed and manifold vacuum opens the choke valve a fixed amount. The fixed amount is determined by the balance of manifold vacuum and choke opener spring tension.

During warm engine starts, while engine is being cranked, the cranking leak solenoid is energized so that the choke remains in its partially closed position. When the engine is started and ignition switch is returned to the "RUN" position, the cranking leak solenoid is de-energized, allowing thermovalve to close. As thermovalve closes, full manifold vacuum is applied to the choke opener.