Abstract: A fuel shut-off system for a carburetor substantially reduces or prevents the delivery of fuel to an engine when the engine is turned off and as it coasts to a stop. The fuel shut-off system preferably reduces or eliminates the pressure differential across a nozzle through which fuel is delivered from a fuel chamber through a fuel-and-air mixing passage of the carburetor and into the engine. In this manner, the flow of fuel through the nozzle is reduced and preferably eliminated immediately upon engine turn-off to prevent the after-fire and associated problems within a residually hot exhaust system. The system incorporates an actuator, preferably a solenoid valve, having a first position which obstructs a vacuum bypass passage communicating between the fuel chamber and the fuel-and-air mixing passage, and a second position which enables communication between the vacuum bypass passage and a fuel chamber passage which otherwise communicates with a near atmospheric pressure source.

Abstract: A carburetor for a small internal combustion engine has a manual priming fuel pump with a resilient valve for allowing fuel flow in a first direction and for preventing fuel flow in a second direction. The resilient valve is reinforced with longitudinally extending ribs to prevent recirculation of fuel through an outlet orifice of the valve in a running engine. The outlet orifice is defined by a distal end of a tubular portion of the valve press fitted and projecting into an outlet passage that communicates with a pump chamber defined by a resilient domed cap. The ribs project laterally outward from the tubular portion within the outlet passage. Integral with an opposite end of the resilient valve is a head which flexes outward to open an inlet passage which then communicates with the pump chamber.

Abstract: A carburetor has an upper body and a lower separate nozzle post member that extends into the fuel chamber of a lower fuel bowl. The nozzle post member has a main nozzle mixing passage leading from a main fuel jet inlet to a nozzle. An annular air passage and an annular idle fuel passage surround the mixing passage. The nozzle post member also has integrally formed brackets to pivotally mount the fuel float.