There are two kinds of flooded engines. The first is an internal combustion engine that has been fed an excessively rich air-fuel mixture. An engine in this condition won’t start until the fuel has been cleared, but it isn’t damaged. However, a flooded engine that was submerged underwater is different, and the odds are good the engine is totaled and will need to be replaced. Have a mechanic take a look at the engine to find out if it could be repaired.