I have a Coleman CT200U. My son went through some deep water which caused it to the run rough. I fixed the carburetor which had some dirt in the throttle body and it seemed good. Well the engine Now runs really rough and very little power to go. Throttle wide open the engine sputters. Thought it was the plug and it was black (rich) so I replaced it.also slight backfire from the exhaust like a burst of flame shot out. It looked Pretty cool but not what I want right now. No work has been to the motor and Carb seems ok and clean. Anyone have an ideas what it maybe? I’m thinking something to do with the valve. But before I remove the cover just wanted to get some input. Thanks in advance.