On some engines somtimes a little of the fuel spray comes out the front of carb.A proper velocity stack keeps this fuel from coming out of carb and goes back into engine and also increases air flow.In order for yours not to work properly in my opinion you would have to have a visible space around the base.if theres any kind of a gasket under it i doubt if your leaking or sucking air.check all gaskets to see what they look like and see if your pulse hole is clear and the holes in gaskets and everything line up and arnt blocked or plugged.