Abstract: A carburetor with a pressurized fuel source is provided. The carburetor has an upright passage extending therethrough with an intermediate fuel-supply portion in which is located a fuel injection tube having a plurality of orifices extending therealong through which fuel is directed under pressure into the passage. An air-control slide valve is mounted for movement across the passage between an open and a closed position and has a closure member or plug which regulates the number of orifices of the injection tube through which the fuel is supplied. The closure member is connected to the accelerator pedal in a manner such that the member opens at least one additional orifice during acceleration before the air-control slide valve opens more, to provide additional fuel during acceleration. Also, during deceleration, the closure member closes at least one additional orifice before the slide valve moves toward the closed position.