I have a 1983 350 260 hp in my 27 ft carver I have put on a new stern drive so the impeller is new all new hoses and manifold and risers took it out about a month ago and it ran fine took it out last night and it sounded like a belt was slipping a god awful screeching and the temp started rising the therm stat is also new I did not replace engine water pump that is belt driven and more than likely it is bad . The only reason I ask this is because when I throttled up to about 1500 rpms the screeching stopped but it kept getting hotter.I plan on replacing water pump but any other things I should look for?