Recently my Sachs Seville with the Bing 85/12/104 started throwing gas through the exhaust after shutdown. To the extent engine would almost be frozen next time I tried to start. Fuel petcock confirmed in off position. Fuel line pulled when sitting to make sure petcock isn't leaking. I've started running the engine with petcock off to use up inline fuel. Obviously I'm not a carb expert but is there one out there willing to enlighten the ignorant?