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Not even close to being an authority. My experience with the ones I’ve had – if its brass, (screws – nuts – bolts) it was nickel plated. Copper water lines, fuel line’s, and brass fittings, were nickel plated. Water pump nickel plated. This 1923 I had, that I believe was original, still having the original plug wires, had nickel plated cylinders. Nothing painted. Although I’m struggling with it, search you tube for nickel plating. I have only tried to do small (brass) stuff. No cylinders. Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.