I put my boat in the water for the first time and everything was fine until suddenly it shut off. It started fine again but then I heard a funny noise. I pulled it out of the water again and checked the engine. I'm hearing a funny rattle when I put pressure on the flywheel. Compression seems to be fine since the engine will catch right away. I'm thinking it's the main bearings but I was wondering if it could be something else. Any other suggestions would be appreciated.