Overheatng Problem

[sweetseason]

wow! thanks for all the information. My best hope is that there is just some build up or old impeller parts stuck and clogging somthing. They have to be somewhere because I saw what was left of the old ones. From my understanding the heat exchanger might be a source of a blockage. It will be a few months before I get into this project, but I think I will start with ordering new gaskets for everything having to do with the cooling system so when I dissasemble everyhing for a detailed cleaning I can put it back together properly. If it is a cylinder or compression problem I will be lost on where to go from there. I did have the original 79 engine replaced with a rebuilt 82 two years ago and it ran right for a half of a season took the boat back to the guy at the end of the year to fix the problem. He said he replaced the impellers in the water pumps. long story short its got to be somthing simple because the two guys after him cant figure it out either.
I did replace the radiator cap that was rusted and faulty
Is there a way to save this thread so I can go back to this information?
Also it was mentioned that I might be able to bypass the heat exchanger?
Is there a way to modify the system so that it cycles raw water like every other boat?
I live in Michigan so I am not concerned about having this closed system anyway