[LNP]

Geezer's right the secondary butterfly will not open on a free rev. If you looked into the venturi after shutting off the engine and fuel is running out of the discharge nozzle then I would start with excessive float level, bad float, or too much fuel pressue. Even after shutting off the engine it takes a moment for the pressure to drop. If the fuel bowl level is to high it will leak fuel out the discharge nozzle until the level is more normal. These issues will cause hard starts on quick trips to the store but will go unnoticed overnight.