Walbro Engine Management, L.l.c.

Walbro Corporation

Paul S Learman

Gary U Gliniecki

George M Pattullo

Michael P Burns

Dale P Kus

David L Thomas

Timothy K Grifka

Anthony M Kueffner

Bradley D Hilbig

Larry D Whittaker

Jeffrey H Krueger

In at least one implementation a carburetor includes an intake bore with a port opening into the intake bore, a fuel chamber from which fuel is supplied to the intake bore, and an accelerator device including a fuel reservoir. A fuel flow control valve is provided between the fuel chamber and the port to control the flow rate of fuel to the port and at least one passage communicates the fuel reservoir with the port and fuel in the fuel reservoir is supplied to the port therethrough. The passage also communicates the fuel reservoir with the fuel chamber. The fuel flow control valve is located between the fuel reservoir and the port and between the fuel chamber and the port, and the passage includes a portion extending between the fuel reservoir and the fuel chamber independently of the fuel flow control valve.

Accelerator device for a carburetor

A purge and prime assembly for a carburetor includes a purge and prime pump that alternately takes in and discharges fluid, and a plurality of passages through which fluid is routed. The passages may include a purge passage through which fluid is drawn by the purge and prime pump, a return passage through which fluid is discharged from the purge and prime pump and discharged from the carburetor, and a priming passage through which a portion of the fluid discharged from the purge and prime pump is routed to a main bore of the carburetor. The assembly may also include a purge valve that prevents fluid from being discharged from the purge prime pump through the purge passage, and a return valve that prevents fluid in the return passage from being drawn into the purge and prime pump.

Carburetor fuel supply system

A carburetor including a main body and a throttle valve received in a mixing passage through the main body. The throttle valve is movable to adjust the quantity of a fuel and air mixture supplied to an engine. A carrier member on the main body has a threaded bore in which a shank of an idle speed adjustment screw is received to adjust and control the idle position of the throttle valve. The idle speed adjustment screw is formed of a polymeric material such that the shank is deformed by engagement with the threaded bore to reliably retain the idle speed adjustment screw in its adjusted position in the threaded bore.

Carburetor with plastic idle speed adjustment screw

A carburetor having a throttle valve co-rotatable with a small diameter throttle shaft having a free end protruding from an exterior side surface of the associated carburetor body. A throttle lever detent arm is co-rotatable on and with the throttle shaft free end adjacent each body surface. Interengageable detents on the detent arm and body surface are spaced radially away from the throttle shaft rotational axis by a distance, for example, of about three times the shaft diameter. The arm and body detents are releasably engageable with one another for thereby yieldably holding the detent arm and hence the throttle shaft and associated throttle valve in any one of a plurality of selected angular settings. Hence, the angular tolerance variation on the set positions of the throttle valve blade as controlled by the detents is now, for example, approximately three times more precise so that the tolerance limits for such positions are now rendered three times tighter than otherwise would be possible when utilizing the prior art. Hence manufacturing tolerances do not need to be tightened up in order to achieve the exemplary three-fold improvement in operational tolerances of the carburetor throttle control detent mechanism. The invention thus provides a low cost throttle control detent mechanism that enables fine increment, positive stops at predetermined valve blade settings, such as the W.O.T. (wide-open throttle), idle and closed valve positions.

Carburetor throttle control detent mechanism

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.

Growing community of inventors

Bad Axe, MI, United States of America

Paul S Learman