It won't if you turn your prop so that the intake hole in the crank is closed. But the amount of fuel that's going to be pressured through the spray bar into that crank hole depends on how hard you pump the fuel into the airplane. Sometimes if you pump easy there won't be any fuel out the spray bar. Also, the mounting direction of the engine may tend to slowly turn the crank back open, or it might hold it closed for you. And obviously if your carb opening is pointing toward the ground any fuel flowing out the spray bar is going to drip out of the carb.