All carbs will work with either pump fed or gravity fed fuel supplies. Your problem is your float valve in the carburetor. Either the valve itself is defective or the float level needs to be set.
Is the carb new? If it is used, was it set up for alcohol? Methanol alcohol will eat up rubber, and as you might have guessed the tip of the float valve is rubber and it is what maintains the fuel level in the carb bowl. If the seal is compromised, your carb will leak like a flour sieve. Your problem is a simple fix, a rebuild kit for a Keihin is less than $25