Outboard Engine Ethanol Protection

Three tips for protecting your boat from E10 gasoline.


Outboard Engine Ethanol Protection

Let’s assume the adventure you have been planning does not include the episode where your boat is bobbing dead in the water while you troubleshoot a tank full of crappy gas. Here’s how to avoid that scenario. Ethanol remains the leading culprit of fuel issues in gasoline-powered marine engines — ethanol is corrosive, it’s a solvent, and it absorbs moisture. In a boat it’s nothing but trouble. The obvious action is to not fuel your boat with an ethanol-blend gas. When that’s not an option, you need an ethanol defense strategy, like these tips we’ve gleaned from Yamaha Marine.

1. Install a 10-micron water-­separating fuel filter for each engine. Then carry at least one spare element for each filter on your boat. Make sure the filter has an adequate flow rating. Yamaha’s big filter flows 90 gph; its smaller filter flows 60 gph and is for outboards less than 115 hp. Yamaha says its filters achieve 95 percent filtration, almost double the 51 percent filtration rate required for the 10-micron rating. That’s right — a filter can carry a 10-micron rating and still allow 49 percent of debris larger than 10 microns to pass right on by. Here’s where I become an advocate for using products branded by original equipment manufacturers. When a motor builder puts its brand on the label of a filter or an additive or oil, it puts its warranty on the line. OEM products invariably exceed minimum standards. Why settle for any but the best products for your very expensive marine engine — to save a few bucks? Be smart and buy cheap beer instead.

2. Use a marine-­specific fuel stabilizer at the correct ratio in every tank of fuel to prevent oxidation and phase separation. Yamaha says its proprietary stabilizer formula features anti-corrosive components that protect exposed copper, solder and other metals from the nasty sodium sulfate present in ethanol. Yamaha stabilizer is petroleum-based, rather than alcohol-based, because why would you put an alcohol-based fuel additive in a boat tank? Sniff that stabilizer you’ve been using. If it smells like rubbing alcohol, don’t use it in the boat.

3. Finally, Yamaha recommends use of its Ring Free Plus additive. As its name implies, Ring Free was originally developed to prevent carbon buildup in the ring lands of two-stroke outboards, but this latest formula is a great dispersant with a dose of corrosion inhibitors. Ring Free will be especially helpful if you are running an older motor with carburetors that are prone to gunking up.

Quick Tip: Use a wrench to remove filters, using a scrap of sandpaper for grip, if required. Install replacements “hand tight,” and always check for leaks.


Outboard Engine Ethanol Protection | Boating Magazine.

Published by Hank Sibley Bluewater Yacht Sales

Hank Sibley hsibley@bwys.com Sales Professional Bluewater Yacht Sales Hampton, VA 804.337.1945 (Mobile) 757.788.7082 (Office) 757.723.3329 (Fax)

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