If you’re serious about keeping your engines looking sharp always have a can of touch-up paint onboard. Nothing shouts shoddy maintenance louder than a rust-patched, paint-flaking motor, and it’s easy to avoid. You don’t have to be Rembrandt, either: Basic prep and a light touch with the spray can are all it takes.
Scrape off flaking paint and knock off loose rust with a brass- or bronze-wire brush, taking pains to control the metal bits and dust. Feather the paint edges with sandpaper or emery cloth, and wipe off any remaining dust with a rag moistened with rubbing alcohol. Prime the metal with Ospho or another rust converter to form a solid, rust-resistant base for the new paint.
Engine manufacturers sell touch-up kits in the appropriate colors, and Dupli-Color and PlastiKote both make paints to match common engines. Your local auto-parts store may carry them. (Use engine paint that can withstand high temperatures.) If the paint manufacturer recommends a primer, and you’re feeling ambitious, order it, too. I’d be OK with painting right over the Ospho, however.
Mask the area you’re painting using whatever creative method comes to mind. Masking tape is a pain on engines, so I usually just drape old rags where I don’t want overspray. If there’s no way to mask small areas, smearing them with Vaseline will keep paint from sticking. Let the paint dry and wipe it off. Spray the touch-up paint on in multiple thin coats, letting each coat tack-dry for a minute or so. Too little paint is better than too much. When you’re done, invert the spray can and blow out the nozzle, then stow it for next time.
Mike Smith is a technical contributor for our sister publication Power & Motoryacht.