Sorry to be the one to say this but maybe you need to seek the help of a professional (or at least someone who is knowledgable about engines/ boats)?...

I realize your boat is on a lift and not easily accessible for a mechanic to get to, but you could be chasing your tail for a while and losing good water time.

There is a certain level of knowledge that is necessary to troubleshoot this sort of thing and it seems like it would be a steep learning slope. I don't mean any offense by my comments, I am mostly concerned with your lack of water time while you sort your way through this.