How do you start a flooded lawn mower?

If you are sure it is flooded you could take the spark plug out and wipe it clean with a wire brush. Start over with it out just for a second then put plug back in and try it. If you do not what to do that, you can wait and it should start in about 20 to 30 minutes. If you are in a space that allows (and wear appropriate protection), you can pull the spark plug and then crank the engine. Gas mist or even drop will come out if it is flooded. So you dont want to crank while over grass just in case gas comes out.

That is almost true but never clean the spark plug on anything with a wire brush, you could mess up the gap on it. The best thing to do is to just not touch it for about ten minutes and allow the extra gas to go back to the tank then yes it will start.