my transom is starting to get some pinholes in it but the rest of the boat is solid, should i put an anode on the boat or motor? which kind? zinc or magnesium?
Not unless the boat sits in the water all of the time. If it's trailered, no anodes are needed. If it does sit in the water all of the time, I would have the pin holes repaired then paint the hull. Anodes on the outdrive and trim tabs.