Abstract: A vacuum motor suitable for actuating a carburetor choke valve has primary and secondary stages responsive to separate vacuum signals. The secondary stage is carried by the primary stage and has a valve which opens upon full retraction of the primary stage to permit application of a vacuum signal to the secondary stage.

Abstract: In an internal combustion engine carburetor the idle mixture adjusting valve is supported in a guide member. A sleeve slides on the guide member and carries a closure portion engageable with a seat surrounding the idle fuel discharge port. A solenoid energized during deceleration moves the sleeve to engage the closure portion with the seat and interrupt fuel flow through the discharge orifice.

Abstract: In an internal combustion engine carburetor the idle mixture adjusting valve has a tapered metering portion disposed in the idle fuel discharge orifice and a separate closure portion engageable with a seat. A solenoid energized during deceleration moves the valve to engage the closure portion with the seat and interrupt fuel flow through the discharge orifice.

Abstract: The level of fuel in the float bowl of a carburetor is controlled by a semi-spherical inlet valve that is carried by an ambient pressure responsive aneroid-toroidal float assembly in position to coact with a vertically adjustable seat on a fuel inlet whereby the level of fuel in the float bowl is compensated for pressure and altitude variations.

Abstract: In a carburetor having a two-stage power valve and an off-idle air bleed, a lean air-fuel mixture may be supplied when it is desirable to operate in a lean mode for optimizing an exhaust gas oxidizing reactor while a rich air-fuel mixture may be provided when it is desirable to operate in a rich mode for optimizing an exhaust gas reducing converter. In the rich mode means comprising a selectively energizable solenoid control closes the off-idle air bleed and opens the first stage of the power valve thereby enriching both off-idle and open throttle air-fuel mixtures. The power valve is also operated by an induction pressure responsive piston, and at high induction pressures both stages may be opened during lean mode operation and the second stage may be opened during rich mode operation for wide open throttle enrichment.