Dashpot System

This system slows the closing of the throttle. During periods of deceleration, ported vacuum in the carburetor acts on the throttle control valve through the dashpot check valve to hold the throttle open slightly. The fixed orifice in the dashpot check valve gradually decreases the vacuum until the throttle closes completely.

The speed at which the throttle closes is determined by the size of the fixed orifice in the dashpot check valve, the tension of the throttle return spring, and the amount of vacuum generated at the carburetor port above the preset level in the dashpot check valve.