US Patent 7104526 Carburetor with intermediate throttle valve blocking position

A carburetor including a frame having a first air/fuel channel and a second air channel; and a throttle valve assembly connected to the frame and having two valve sections. Each valve section is located in a respective one of the channels. A second one of the valve sections has an air bleed hole therethrough. The second valve section is movable relative to the frame from a first idle position to a second intermediate closed position and then to a third open position at a wide open throttle (WOT). The air bleed hole allows flow through the second channel at the first idle position, but does not allow flow through the second channel when the second valve section is at the second intermediate closed position.