So I wonder... Is there another cooling system available for that(or near) year production? I had a Mercury Promax a while ago. For that particular model over several years, there was 2 different cooling systems. Different pump housing, different tube, different gaskets. My motor came with mix matched parts. Some for one system, some for the other. After the second time it burned up pistons, I researched it further and found a guy that explained this to me on Fastbass. After all the proper parts were installed, no more issues. Just a thought. All the part #'s were correct for the motor, on paper. They just didn't work together.