Staged single venturi carburetor

Claim 1

A low silhouette dual flow stage carburetor having an air/fuel induction passage open at one end to air essentially at atmospheric pressure and adapted to be connected to an engine intake manifold at its other end, a throttle valve rotatably mounted in said passage for movement between closed and wide open positions to control flow through said passage, a sleeve-like fuel and air flow control member mounted anterior of said valve and spaced from the walls of said passage, said member having an outer annular arcuate contour of a profile so as together with the walls of said passage define a fixed area venturi, a valve member concentrically mounted within the hollow interior of said member and movable between positions closing or opening the said interior of said member, a fuel nozzle opening into said passage at a point adjacent said venturi so as to be subject to the varying pressure signal therein for the flow of fuel at times therefrom into said passage, said valve member in its closed position defining an initial stage flow at low throttle valve angle positions and low air flows providing a high venturi fuel metering signal, movement of said valve member to a second stage wide open throttle valve position providing high air flow through said passage, and means to move said valve member.