At the end of last year, I did many of the gaskets on the powerhead, including where the powerhead mounts on the plate. Motor ran great after the new gaskets, but it took a long while before cooling water came out the back before I put it into storage. And the lower unit was milky. Start up at the beginning of the season, it also took a long time before water started spitting out the back holes. I knew it had been a few years since I last replaced the water impeller. I found a used lower unit, put on new water pump impellor and this weekend I attempted to swap. When I reinstalled my good used lower unit the plastic piece that funnels the water from the water pump to the copper tube was still stuck on it from the other lower unit. Therefore I pushed it together with two of those plastic pieces. It ran the best it's ever run in the 8 years I've owned the boat……until the overheat alarm came on. I removed the lower unit again, and that is when I discovered I had put the lower unit on with both the plastic pieces. I reinstalled the lower unit with one of the plastic pieces. It only ran for a few minutes and the alarm came on a again. Any suggestions on getting a better fit to the water pump? Is it possible I bent the copper tube? Since I may have pushed the copper tube up too far, can I pull on it to bring it further down? Any suggestions would be appreciated.