Staged carburetor

In a staged multi-barrel carburetor for an internal combustion engine, the carburetor having at least two air induction passages and first and second throttle valves one of which is positioned in each of the respective induction passages, each throttle valve being movable between a closed and an open position and the first throttle valve being operable to open prior to the second throttle valve opening, and a countershaft interconnected with the first throttle valve for rotation therewith as it opens and closes, the improvement comprising;

• means interconnecting the countershaft with the second throttle valve to open the second throttle valve as the first throttle valve opens;
• means carried by the countershaft for producing movement of the interconnecting means to open the second throttle valve after the first throttle valve has opened to a predetermined open position;
• and
• means responsive to the vacuum in the engine for delaying opening movement of the second throttle valve after the first throttle valve has opened to its predetermined open position if engine vacuum exceeds a predetermined level thereby to prevent lags in engine performance which may occur during engine acceleration.