Abstract: A vacuum-operated air-valve actuator has a vacuum chamber held in communication with the intake air passage not only at a point between the air valve and the throttle valve but also at a point on the downstream side of the latter. In low load engine operation, the actuator is fed with a relatively high vacuum occurring on the downstream side of the throttle as well as with a lower vacuum in the Venturi and acts to increase the opening of the air valve. As the result, the vacuum in the Venturi, under which a fuel metering device operates, is reduced and accordingly the amount of fuel metered out is reduced to minimize the density of unburnt ingredients in the engine exhaust gases.

Abstract: A starter assist device for internal combustion engines which includes a supplemental air supply passage for the intake manifold arranged to bypass the carburetor, and a thermo-sensitive switch incorporated in the starter circuit and arranged to cause introduction of supplemental air into the intake manifold when the engine is started under conditions in which the engine is warm so that an oversupply of fuel is avoided, and to close off the supplemental air when the engine is started when cold to provide an adequate amount of fuel.

Abstract: A device which prevents run-on continued operation of an internal combustion engine when the ignition is shut off: the device including means for preventing delayed closing of the throttle valve or valves when the ignition circuit is opened.