Quicksilver Blog

How to Touch Up Marine Gearcase Paint

It is not unusual for paint to wear away from the skeg (the fin forward of the propeller) and lower gearcase of an outboard or sterndrive, revealing the cast aluminum housing. When this happens, it’s good practice to touch up the paint.

Paint may wear from the lowest areas of the gearcase if the drive frequently contacts the bottom, especially if that bottom is sand, gravel or otherwise abrasive. One function of the skeg is to protect your expensive prop from an abrasive bottom, so it’s natural for the paint to wear. Once that paint is gone, any bare aluminum surface will be prone to corrosion, especially if you are boating in saltwater. If your boat has a stainless steel propeller and you boat in saltwater, bare aluminum on the gearcase, close to the prop, sets up the potential for harmful galvanic corrosion. Touching up your gearcase paint will also make it look nicer and may enhance resale value.

Quicksilver® offers the right paint products for a do-it-yourself touch-up of any Mercury® or Mercury MerCruiser® gearcase, including convenient spray cans of Quicksilver Light Gray Primer, Quicksilver Phantom Black paint and Quicksilver Leveler. Quicksilver Phantom Black paint is not only an exact color and finish match for the original Mercury or MerCruiser paint, it is also specially formulated for the marine environment, with UV blockers not typically found in standard hardware store spray paint. This is especially important if your outboard-powered boat is frequently moored with its motor tilted up and exposed to the sun.

Prep Work Matters

As with any painting project, a quality end result begins with careful preparation of the surface before paint is applied.

  • Remove the propeller to protect it from paint overspray and protect the propshaft with a rag or newspaper.
  • Clean the area to be touched up to remove all oil, wax, grease, salt or other marine build‑up with an appropriate marine cleaner such as Quicksilver All-Purpose Spray Cleaner. You can also use a solvent-type wax remover, grease remover or naphtha.
  • If the exposed aluminum is pitted or is showing paint blisters, start by sanding the affected area with 180 or 220 grit sandpaper. Finish and feather into the surrounding paint with 320 grit sandpaper by hand. Finally, use a medium maroon Scotch-Brite® hand pad (available from paint or hardware stores) to scuff the bare aluminum and the paint to approximately 1 inch outside of the damaged area to aid paint adhesion. Complete a final wipe with a wax and grease remover or naphtha. Lightly remove dust with a tack rag.
  • Prime the area with Quicksilver Light Gray Primer following instructions on the can. After the primer is dry, scuff lightly with a medium maroon Scotch‑Brite pad to feather the edge of the spray into surrounding paint and to promote adhesion. Do not penetrate the primer.
  • Apply Quicksilver Phantom Black paint, following instructions on the can. For best results hold the can 8 to 10 inches from the work surface. Apply several thin, even coats rather than a single heavy coat. Let the paint set up for 10 to 20 minutes between coats.
  • For a superior finish, apply a coat of Quicksilver Leveler before the final coat of Phantom Black paint dries. Leveler is not required for a durable paint finish, but it can help smooth out imperfections. Wait at least 24 hours for the final coat to cure before placing the boat in the water.

An annual touch-up with quality Quicksilver paint products provides important protection for your engine’s lower unit. Go to Quicksilver.com for retailer information.

Pro Tips

  • Never paint over sacrificial anodes (“zincs”) as the anode material needs to be in contact with the water to offer corrosion protection. Either mask off or remove an anode if you must paint near it.
  • When you are finished using any Quicksilver spray paint product, clear the nozzle by turning the can upside down and pushing the spray button until clear gas comes out. This will prevent dried paint from clogging the nozzle before the next use.
  • Scratches in the paint that do not penetrate the original black primer can be quickly touched up using the Quicksilver Mercury Phantom Black Paint Pen. Its brush-like tip makes it easy to fill in scratches, and the color will perfectly match the original factory paint.


Scotch-Brite is a registered trademark of the 3-M Corporation. All other trademarks belong to Brunswick Corporation.