A fuel supply device has a base body, in which an intake channel section is formed. At least one adjustable throttle element for controlling the free flow cross section of the intake channel section is provided. At least one fuel opening opens into the intake channel section. A partition wall section is arranged in the intake channel section upstream of the throttle element. The partition wall section and the throttle element divide, in a completely open position of the throttle element, the intake channel section upstream of the throttle element into a mixture channel, into which the fuel opening feeds fuel, and an air channel. In order to improve the cooling of the fuel supply device, the partition wall section has at least one element for increasing the surface area within the mixture channel.

A carburetor having an inlet opening that includes a pair of concavities operative to direct air toward the metering rod of the carburetor. A carburetor having an inlet opening that includes an arcuate manifold adjacent to the inlet opening and in fluid communication with a fuel reservoir. A carburetor having a slide assembly that includes a positioning mechanism operative to adjust the position of the metering rod relative to the throttle slide. A throttle slide that includes a flow guide that bisects an arcuate relief on an underside thereof. A method for configuring the throat of a carburetor that includes an upper portion of a first diameter and a lower portion of a second diameter that is offset from the first diameter. The method comprises deriving an optimum size for the first and second diameters and the offset based on the pumping efficiency and operating parameters of the engine.

A mixing manifold is provided. The manifold includes: a body; a first converging passageway in the body; a first diverging passageway in the body in-line and in fluid communication with the first converging passageway to form a first venturi; a first obstruction in a throat of the first venturi configured to move between two positions, a blocking position that blocks, at least in part, flow through the first venturi and an open position; a second converging passageway in the body; a second diverging passageway in the body in-line and in fluid communication with the second converging passageway to form a second venturi; and a second obstruction in the second venturi configured to move between two positions, a blocking position that blocks, at least in part, flow through the second venturi and an open position. A method of providing fluid flow through a manifold is also provided.