have you checked for AC output at the gen? make sure it's not just a breaker off. there should be an AC breaker on or near the gen.
failing that. definatly get it looked at. if it's easy to fix, get it fixed. maybe he will have it running in 15 mins. if they tell you something really bad. and quote thousands. then make that choice after it's looked at and you know things.
personally no portable gen should be on a boat
. you are basically saying you can't afford to do it correctly and safely. so maybe you will do it wrong instead. that is not how you do things on a boat
. lives are at stake. yours, other boaters, and coast guard members.