I have never really been around jet boats, but i am looking to get one. I found a 18ft galaxie, with berkley pump, and new int. Has a 454, that needs rebuilt. It seems to be a decent fixer upper, but what should i look for when checking it out. What is the difference between a marine engine and automotive? I'm sure the engine itself works basically the same, but what is the main difference? Thanks for any help.