I agree with some of Putershark's points. I assume that you will be buying a new motor. Yes old 2 strokes smelt bad and had problems and old four strokes are heavy and can cost alot to fix. I have a 75hp etech {2 stroke} that is light, fast and good on fuel. It is the cleanest burning 2 stroke out there and I would put it against any 4 stroke for emissions. There is no smell of fumes at all.It is also as quiet as a 4stroke. I agree that you don't need to go 75 mph in your triumph, but if you are pulling anyone or carring a heavy load an etech will get you on plane faster. As for resale I don't know. 2 or 4 stroke there are a lot of good choices out there, just thought I would give you my 2 cents worth, Good luck with your new boat. Bob