Variable venturi carburetor

A variable venturi carburetor, comrpising a housing having an inlet, an outlet and a passageway therethrough connecting the inlet with the outlet, said passageway including generally parallel end walls, and side walls having first portions which converge from the inlet to a rectangularly shaped throat intermediate the inlet and outlet and second portions which diverge from the throat to the outlet, said first side wall portions being swingable about axes adjacent the inlet and said second side wall portions being swingable about axes adjacent the outlet so as to adjust the size of the throat, a pair of shafts each mounted within the ends of the housing and for rotation about an axis parallel to the axes about which the side wall portions are swingable, and extending within the housing intermediate the outer side of each side wall of the passageway, cams rotatable with the shafts in one direction to move the adjacent ends of the side wall portions toward one another to narrow the throat and in the opposite direction to permit said portions to move away from one another to widen the throat, a port in the end wall of the passageway for sensing pressure therein downstream but immediately adjacent the throat, means including a chamber having a diaphragm therein and a conduit connecting the chamber with the port so that the diaphragm reciprocates in response to the sensed pressure, means connecting the diaphragm to the ends of the shafts which extend from one end of the housing so as to rotate them in said one direction as the speed of the engine decreases and in said opposite direction as the speed of the engine increases, an elongate fuel nozzle extending parallel to the throat just upstream thereof and providing the only restriction in the passageway, a fuel bowl at the other end of the housing, a conduit connecting the fuel bowl with the nozzle, a valve element movable in the connection of the conduit to the bowl for controlling the flow of fuel from the bowl into the conduit, and means on the end of one of the shafts which extends from the other end of the housing for moving the valve element to a position to increase the flow of fuel as the speed of the engine increases and to permit the valve element to move to a position to decrease the flow of fuel as the speed of the engine decreases.