Have now discovered that my newly purchased 1995 Grady White 208 had a very minor two stroke external oil reservoir leak. It was simply leaking a few drops from around the filler neck hose and tank after every fill. This small amount oil oil over time had been making its way to the lowest point, ie the bilge. After mixing with saltwater the sticky gunk had entered the sealed bilge pump float switch and rendered it intermitant at best. The previous owner had also removed the strainer screen from the bilge pump intake rather than fixing and cleaning the oil problem. So the impeller had several chips out of the impeller blades due to junk getting inhaled. Replaced pump switch and all wiring and fuse assembly.
