Took my boat out yesterday. Started right up, idled fine. After about 1/2 hour, turned it off. Couldn't get it started for about 20 minutes. I took the plugs out, and they looked dry. I got it started finally, and the same thing happened a couple of more times when I stopped and then tried to start it. Took the carbs off, took them apart, looked perfect, no gum deposits or crud. Took the low speed idle jets out, blew carb cleaner through everything, everything seemed fine. Changed gaskets, o-rings. If this doesn't work, any suggestions on what I should check? I took the fuel screen out, and it looked clean. The engine runs great at all RPM, just won't start when hot. It's got new fuel I bought yesterday.