Do what Mike said. If you over choked your engine that can flood it, if you have A tank with fuel in it and your plane was upside down or nose down that can flood one. If it's flooded like that and you have A good electric starter you can break and bend some of your engines favorite parts. If A plane has A full fuel tank and it's sitting out in the hot sun I have seen the engine draw [siphon] fuel and flood itself. Most the time doing what Mike said works very well and is A lot easier then taking out the plug.