My 92 OMC 8 hp O/B had a cracked exhaust gallery cover when I got it this spring as part of a boat deal. Former owner apparently did not flush it adequately, and then must have let it freeze while wet inside. The bolts holding the water gallery/exhaust cover on were galvanically seized and so they broke off in the block while being (carefully) removed for repair. The motor is now scrap as a result of this. Galvanic corrosion is the reason. Moral of the story is that if you buy a new outboard motor and you plan to use it in salt water, have all the engine bolts removed, one at a time, and coat the threads with an anti-sieze compound, before you get it wet. Salt water penetrates into the bolt threads, then its too late. Galvanic corrosion happens fast in aluminum alloy castimgs. Another moral..avpoid buying a used O/B that has been in salt water. Caveat emptor.