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How to Touch Up Mercury Gearcase Paint

Get your motor back in the black.

Quick Tip: How to Touch Up Mercury Gearcase Paint

Is your Mercury lower unit looking shabby? It is not unusual for paint to wear through to bare metal from the skeg and lower gearcase of an outboard or sterndrive, especially if your boating adventures frequently bring your skeg in contact with sand, gravel or otherwise abrasive bottoms. One function of the skeg – the fin forward of the propeller – is to protect your expensive prop from an abrasive bottom, so it’s natural that the paint may wear. Once that paint is gone, bare aluminum surfaces are more prone to corrosion, especially if you are boating in salt water. If your boat has a stainless steel propeller and you boat in salt water, bare aluminum on the gearcase is very close to the prop and increases the potential for damaging galvanic corrosion to occur. Touching up your gearcase paint will make it look nicer, and may enhance its resale value.

Mercury Authorized Dealers offer the best Mercury Precision Care® paint products for a do-it-yourself touch-up of any Mercury® or MerCruiser® gearcase, including convenient spray cans of Mercury Light Gray Primer and other colors that match original Phantom Black Verado® Silver, Cold Fusion White and Warm Fusion White and Pearl. Mercury paint products are an exact color and finish match for the original factory-applied Mercury or MerCruiser paint, and each 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 result begins with careful preparation of the surface before paint is applied.

  • Remove the propeller to protect it from paint overspray and cover the prop shaft with a rag or newspaper.

  • Clean the area to be touched up by removing all oil, wax, grease, salt or other marine build‑up with an appropriate marine cleaner such as Mercury All-Purpose Spray Cleaner or a solvent-type wax remover, grease remover or naphtha.

  • If the exposed aluminum is pitted or shows paint blisters, start by sanding the affected area with 180 or 220 grit sandpaper. Feather edges into the surrounding paint with 320 grit sandpaper by hand. Finally, use a medium grit abrasive 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 Mercury Light Gray Primer following instructions on the can. After the primer is dry, scuff lightly with a medium grit abrasive pad to feather the edge of the spray into the surrounding paint to promote adhesion. Do not sand through the primer.

  • Apply the appropriate color Mercury paint, following instructions on the can. For best results hold the can 8 to 10 inches from the work surface while spraying 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 Mercury Leveler before the final color paint coat dries. Leveler is not mandatory to achieve 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 Mercury paint products provides important protection for your engine’s lower unit and keeps your equipment looking great.

Pro Tips

  • Never paint over sacrificial anodes (“zincs”) as the anode material needs to be in direct contact with the water to offer protection against corrosion. Either mask off or remove an anode if you must paint near it.

  • When you are finished using any Mercury spray paint product, clear the nozzle by turning the can upside down and pushing the spray button until clear. 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 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.
Quick Tip: How to Touch Up Mercury Gearcase Paint
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