I took the boat out to the bay yesterday and had a great time until...........it stopped. We were going full throttle and then just lost all power. Tried to restart and it just cranks but win't turn over. Almost like trying to start a car without the coil on. I am getting spark out of all cylindres and the coil. The #3 spark plug was fouled. It almost looked like someone put a drop of silver on it. replaced the plug but still wouldn't start. My main concern is that it was in saltwater and I need to flush it. I have a thunderbolt ignition system, Any ideas????