Re: overheating 6hp merc
remove the telltale hose completely from the block. If you don't get flow, you may have to order a set of port plate gaskets, and clean the goo out of the exaust ports and manifold on the port side.<br />I am allmost sure your merc has a head. If so, order a new head gasket,and clean those ports out too.<br />It takes one season in salt water, with no flushing, and you'll have this white corosion clogging every port...Of course, on a 1965 engine, it could just be accumulation. As far as the impeller,it was money well spent,as you should change it whether it needs it or not, every two seasons.