Abstract: A carburetor for an internal combustion engine. A carburetor body has an induction passage for air to be drawn into the engine. A throttle valve is positioned in the induction passage and is movable between an open and a closed position to control the quantity of air drawn into the engine. A staging valve is positioned in the induction passage and is movable between an open and a closed position. The staging valve is closed during engine cranking and is moved to a first open position when the engine starts and toward its fully open position as the engine warms up. The opening movement of the staging valve is limited to a second open position which is less than its fully open position. The limiting of staging valve movement to this second and less than fully open position limits the usable air capacity of the carburetor to less than its maximum capacity.