Re: 1750 fish ski
Just because the original owner was a mechanic does not mean the boat was well maintained. There are a bunch of things that could be wrong and if you really don't know exactly what to look for, you could end up spending way more money trying to get it fixed. I would strongly suggest you take it to a certified marine mechanic to have it gone though fully. It may cost a couple of bucks, but it's money well spent.
Most of these boat manufacturer forums do not get looked at very often. You will get many more responses if you place your questions in one of the regular forums such as the mercruiser forum if it's a mercruiser drivetrain.