The pumparound carburetor is a popular upgrade for moto-based shifter engines to increase reliability and performance. If you've ever had a bog at corner exit with your moto-based shifterkart, chances are a pumparound system will cure the problem. A bog when exiting a corner is usually caused when the high g-loads inherent to karting cause the fuel to slosh to one side of the float bowl. This forces the floats to rise and stay high, which closes the fuel inlet and keeps it closed while the engine uses up the remaining fuel in the bottom of the float bowl.
The carb begins it's life as a Keihin PWK 38mm carburetor. The floats and needle seat are removed and a tube and restrictor are installed. Instead of using only one fuel pump, two are used. One pumps fuel into the carb, and the other pumps excess fuel back to the tank. This way, it is impossible for the engine to run itself out of fuel because it always has a constant supply. The Mikuni round pumps are the pump of choice.
The complete pumparound system includes the modified carburetor, two fuel pumps, and a special mounting manifold for the pumps. This system is legal in most sanctioning bodies even in stock divisions.
Stop the bog
