So are you saying that that motor is not worth rebuilding? I don't want to sink money into it if it's not going to run properly. It needs spark plugs fuel filter and another electrical component. It also needs the carburetors cleaned and synced. Should I not bother doing that work and get a new motor for it? The sn on the boat is 76c. That's the last three digits. From what you said it is a 76 challenger mark II? If so what manufacturer is that? Thanks very much for the help.