Carburetor

In an air valve carburetor having a throat, a throttle valve at the exit of said throat, an air valve at the entrance of said throat, a vacuum responsive actuator for driving said air valve in response to vacuum pressure in said throat, a fuel nozzle disposed in said throat for delivery of fuel thereto, a fuel supply reservoir, and a fuel metering compartment, a fuel supply metering means comprising:

• a generally vertical bore formed in said compartment and having an intake passage at its lower portion interconnected with said fuel supply reservoir and a discharge passage at its upper portion interconnected with said nozzle;
• a cylindrical piston disposed in said bore and reciprocally movable therein, said piston having an outside diameter substantially equal to the inside diameter of said bore to prevent passage of liquid fuel therebetween;
• fuel metering means formed in said bore, said fuel metering means including an orifice disposed between said intake passage and said discharge passage of said bore, and a metering surface on the lower end of said piston disposed to cooperate with said orifice and meter fuel therethrough upon reciprocation of said piston;
• a shaft on said air valve rotatable therewith having an end projecting into said compartment;
• cam means on the end of said shaft;
• a cam follower in said compartment disposed for engagement and movement by said cam upon rotation of said shaft, said cam follower having an action end and anchor end;
• adjustable fulcrum means mounted in said housing and engagable with the anchor end of said cam follower;
• and
• interconnecting means operatively associated with the action end of said cam follower and an upper end of said fuel supply valve piston for interconnecting said piston with said cam follower, whereby said piston is reciprocated in said bore in response to movement of the action end of said cam follower in response to rotation of said air valve shaft;
• said adjustable fulcrum means including a fulcrum shaft reciprocally movable vertically in said housing with a lower end disposed in contact with said cam follower, resilient means operatively associated with an upper end of said shaft and disposed to urge said shaft downwardly, and one-way lock means disposed operatively associated with said fulcrum shaft and disposed to permit downward movement thereof and prevent upward movement thereof.