Abstract: A device for retarding the timing of the spark during the initial phase of acceleration of an internal combustion engine. A bar is connected to the throttle operating linkage and to a valve. Motion of the bar operates the valve to connect carburetor suction to a spark retarding motor. A timing mechanism operates the valve to remove the suction from the retard motor after the initial phase of acceleration.

Abstract: A device for temporarily changing the ignition setting of an internal combustion engine in response to a sudden change of the suction in the intake manifold. A suction operated motor is connected to the ignition timing mechanism to control the suction operated timing of the ignition in response to intake manifold suction changes. The action of the motor is controlled for a selected time interval to reduce the suction operated spark advance for a substantial portion of a normal level road acceleration in city driving as sensed by the change in intake manifold suction.