somethins up with the floats, if the fuel is coming from the overflow that comes from the bowl. Usually its a little debris, and if that is the case, you need to check petcock filter, tank and gas cans for floaties, or anything loose. You have to be sure which hose its comin from too sometimes. It can be the seat where the plunger deal sits on, or the plunger deal can get hung up funny on the rod that it rides on. Someone on here posted, if you blow thru your fuel line then start pushing your floats up, it should stop the air flow, when the floats are level with the carb body. This is with the bowl off of course. Its actually a measurement, but that would tell you, if it was leaking at the float valve before reassembly.