Ethanol and outboards

Regular gasoline is no longer available at retailers’ pumps throughout North Dakota. All pump gasoline, with the exception of premium blends, now contains at least 10 percent ethanol. Regular non-ethanol blended gasoline has been the preferred choice for many outboard motor owners who remain wary of possible negative effects of ethanol.

Ethanol blends contain alcohol. Alcohol dries out plastic and rubber seals, even rubber gas lines and connections in outboard motors. Dry seals and connections are subject to cracking which can lead to poor performance and a trip to the mechanic.

That fishermen are concerned, even confused about what to burn in their outboard motors, is understandable. Even outboard motor manufacturers disagree on the effects of ethanol blends. Yamaha says ethanol-enriched fuel can “wreak havoc on an outboard.” Mercury Outboards says fuels containing up to 10 percent ethanol are “considered acceptable.” Evinrude says “motors can tolerate up to 10 percent alcohol in fuels”.

“What I recommend, if possible, is that customers find non-ethanol gas,” said Mike Neely, Mercury Outboards representative. “That’s especially true if your boat sits for a long time and you don’t use it. If you use your boat quite a bit, E-10 is fine.”

Neely is based in Minnesota where thousands of lakes host thousands of boaters every summer. Most marinas in Minnesota, says Neely, carry only premium gasoline to fill boats on the water.

“Our 87 octane in Minnesota is 10 percent ethanol,” explained Neely. “Non-oxygenated 91 octane contains no ethanol. The higher octane won’t help engine performance, it’s just a grade of gasoline that doesn’t have ethanol.”

Premium gasoline is still sold at the pump in the Minot area, but the price runs about 50 cents per gallon higher than lower octane ethanol blends. Over the course of a season, the difference in price is too much for some boaters to rationalize.

“Now we are forced to deal with it. It’s not the world’s worst problem but it’s not good,” said Jason Foss, North Country Marine in Garrison. “The worst is for boats that sit. If you use your boat constantly there is still lubrication there.”

“The biggest concern is E-10 sitting around and it attracts moisture. It could create condensation,” added Neely. “What you’ll have is the bottom of the tank with water and gas on the top. You can’t shake it up or mix it. You have to drain it.”

Outboard motor manufacturers recommend special additives to combat the negative effects of ethanol. Mercury has three fuel treatment products specifically formulated for ethanol.

“We have Quick Clean, which is more of a once-a-year cleaner for carbon deposits and such,” explained Neely. “We have In-Season fuel treatment for every tank and Quick Store for when you store your boat in the fall.”

Yamaha recommends using Yamalube Ring Free Plus, saying the formula protects fuel system metals from sulfate salt corrosion caused by ethanol usage.

Other companies have gotten into the marine fuel additive market, too. A well-known brand is Marine Formula STA-BIL Ethanol Treatment. While STA-BIL claims their marine formula protects against corrosion caused by water attraction and fuel system plugging caused by deposit loosening, they also say ‘No fuel additive can protect rubbers and plastics that are not designed for exposure to ethanol or other chemicals found in gasoline.'”

Older motors, even newer two-stroke outboards, are more subject to problems associated with burning ethanol than new four-stroke engines.

“With a two-stroke, I’d stick with the non-ethanol stuff,” said Neely. “Carbureted two-strokes are a little more sensitive to ethanol. What we are most concerned about, for all motors, is anything above 10 percent ethanol. With more than E-10 you’ll definitely have some durability and performance issues.”