By Charles Plueddeman
Outboard Expert: Salt Solutions
Tips from an expert to help protect your outboard from salt-water corrosion.
Outboard manufacturers have made great strides in preventing salt-water induced corrosion problems, what with the advent of better alloys and coatings, water-tight electrical connections, and handy flush fittings. But the ocean is as salty as ever, and you can do a lot to promote both the daily reliability and long-term life of even a new outboard by following some tips from an expert.
My expert is David Greenwood, the product planning manager at Suzuki Marine. David has been working for the Suzuki outboard operation for more than 24 years, helping to develop new motors, conducting durability testing on current models, and working on rigging and application issues with Suzuki dealers and boat-builder partners. He also helps out at media events, which is how I spotted him at a Florida launch-ramp parking lot, spraying down powerheads with an aerosol can. I learn something every time I talk with David, and this seemed like a good time to pick his brain, which led to a general discussion of the care of an outboard in salt water. Here are Greenwood’s suggestions:
1. Rinse the Powerhead. After every outing remove the cowl and rinse the powerhead with fresh water. You can do this after you’ve rinsed the motor internally with the fresh-water flush fitting.
“The cowl can’t be water-tight,” said Greenwood, “because we still need to get air to the engine. Most newer outboards have a pretty good intake system that’s designed to separate moisture from the air and drain it away. But the air under the cowl is still sort of a salt-water mist, and over time salt can build up and start corroding electrical connectors, hose clamps, unpainted bolts, and any areas where two pieces of metal come together, or there’s a gasket, and the paint can loosen a little over time.”
So, off with the cowl and out with the hose. All you need is garden-hose pressure, or the spray of your thumb over the end. A high-pressure sprayer might cause damage to electrical connections. Start at the top and rinse down. If they snap off easily, remove any plastic covers from the powerhead so you can do a more-thorough rinse job. Greenwood says it’s safe to drench anything on the motor, but take care to avoid spraying water into the throttle body or carburetor bodies, which could allow water to enter the engine. Then leave the cowl off and let the powerhead dry.
Here’s another Greenwood insight – tests conducted by Suzuki have shown that it takes five minutes of flushing at city-water pressure to remove all traces of salinity from inside the outboard powerhead, using the garden-hose flushing fitting.
2. Apply Corrosion Inhibitor. Spray the powerhead down with a marine-grade silicone product.
Greenwood likes a product called Corrosion Block, available at West Marine and other retail outlets.
“I can say that Corrosion Block is a product that stands up to its claims,” said Greenwood. “I found out about it because one of the engineers that developed the product owned a Suzuki outboard. I ran into him some place, and the motor was about 15 years old and had seen regular use in salt water. He pulled off the cowl and it looked like new. So I asked how he did it. This stuff was his secret.”
Greenwood says that like most silicone sprays, Corrosion Block displaces water, but as it dries it leaves behind a thin coating that does not evaporate away.
“It lasts a lot longer than that famous silicone product,” said Greenwood. “If you are familiar with the LPS 3 spray, the coating is not as thick and waxy as that. But enough stays behind to protect surfaces that could corrode. And from what I’ve seen it’s compatible with rubber, plastics and even the adhesive on electrical tape, which some products will dissolve.”
Over a typical salt-water season, Greenwood recommends three applications of Corrosion Block, and one at the end of the season before winter lay-up. Spray it everywhere.
3. Use Your Grease Gun. Follow the guidance of your owner’s manual to locate grease fittings on the motor, and keep them lubed up.
“I’d do this monthly on my own motor,” said Greenwood. “Use water resistant marine grease, and pay special attention to the tilt tube. You want to keep that clean and freshly greased.”
4. Pull the Prop. Inspect the prop shaft seal area for fishing line, and keep the shaft greased.
“This is another one-a-month habit to get into,” said Greenwood. “The grease on the shaft will rinse away over time, and next thing you know the prop is corroded to the shaft. Fishing line will eat through the shaft seal. Fresh water in the gearcase is bad. Salt water is killer. That’s an expensive repair.”
- Charles Plueddeman is Boats.com's outboard, trailer, and PWC expert. He is a former editor at Boating Magazine and contributor to many national publications since 1986.