Winterizing Boats and Motorcycles with Ethanol Blended Gas

ethanol gas in boats

Winterization tips for your boat or motorcycle to avoid ethanol blended fuel issues

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If you trailer your boat then you most likely fill it up with fuel at gas stations on the road. Let’s face it – it is often cheaper and more convenient than fueling up at the gas dock in the water.

The problem for many boaters is that federally mandated ethanol blended fuel (available at many on-road gas stations) can be very dangerous to your boat’s engine – particularly when you store it for the winter. And as it turns out, motorcycle engines using ethanol fuel can face the same engine problems.

Why is this a bigger problem for boats & motorcycles than it is for cars? It’s because boats and motorcycles are often winterized with gasoline in the tanks… and it’s when you store gasoline with ethanol for longer periods of time that the damage occurs.

(As boaters we experienced this problem first-hand with our previous boat that ran on gas engines. Not only did our boat suffer from poor performance, but we had to have the gas tanks drained and cleaned prior to being able to sell it.)

The Boat Owner’s Association of the United States (BoatUS) and American Motorcyclist Association (AMA) have recently joined forces to help get the word out about proper boat and motorcycle winterization and ethanol’s damaging effects. BoatUS President Margaret Podlich and AMA President Robert Dingman share their expertise on the ethanol issue in more detail as boating and motorcycling season comes to an end this year for many.

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Ethanol Gas Problem

Ethanol in gasoline stored for long periods can damage marine and motorcycle engines: “phase separation” of the fuel can leave a corrosive water-soaked ethanol mixture at the bottom of the gas tank.

Half of the respondents of a recent Boat Owners Association of The United States (BoatU.S.) survey reported that they have had to replace or repair their boat engine or fuel system parts due to suspected ethanol-related damage, costing an average $1,000 for repairs.

Winterization with Ethanol Gas

To prevent ethanol problems over the winter, boats with built-in gas tanks should have fuel stabilizer added and the tank left nearly full. E10 fuel remaining in small portable gas tanks (and not pre-mixed with 2-stroke engine oil) should be poured into your car’s gas tank and used quickly. Same goes for motorcycles – store full with stabilizer or drain completely.

So how did ethanol get into our gas?

Signed into law in 2005 and expanded in 2007, the Renewable Fuel Standard (RFS) requires an increasing amount of biofuels such as corn ethanol to be blended into the gasoline supply. However, the ethanol mandate has failed to achieve promised consumer and environmental benefits.

In addition to winter storage and engine repair concerns, ethanol-blended fuel is actually worse for our air and water. According to research from the University of Tennessee, ethanol’s “clean alternative” record is “highly questionable.” The 2014 federal National Climate Assessment reported that ethanol production can require 220 times more water than gasoline.

Ninety-one percent of those surveyed by BoatU.S. prefer non-ethanol fuel for their boats. An AMA-commissioned poll found that 78 percent of all voters – not just motorcycle owners – have “very serious concerns about E15 use” and 70 percent oppose increasing the amounts of ethanol blended into gasoline.

The Ethanol Gas Issue Going Forward

The Environmental Protection Agency ignores the public’s concerns and continues to increase the amount of ethanol required to be blended in our nation’s gas. Even though it’s illegal to use E15 (15 percent ethanol by volume) in marine engines, snowmobiles, motorcycles, lawnmowers, and any vehicle made before 2001, E15 can now be found in 24 states. Using E15 in many vehicles on the road today will void the manufacturer’s warranty.

With a recent $100 million USDA grant made available to subsidize the installation of blender pumps at gas stations throughout the country, access to ethanol-free gas may soon be more difficult, leading to even more cases of inadvertent misfueling and engine damage.

Thankfully, Congress is considering bipartisan legislation to repeal the ethanol mandate, but the question remains whether our legislators will protect consumers and our environment by eliminating the ethanol mandate.

Contributors to this article: Rob Dingman is the President and CEO of the American Motorcyclist Association, America’s largest motorcycling organization and Margaret Podlich is the President of the Boat Owners Association of The United States (BoatUS), the nation’s largest recreational boat owner advocacy, service and safety group.

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Diane Seltzer

View posts by Diane Seltzer
Diane is the founder of as well as the boating lifestyle site for kids Active in the boating industry, Diane has also led the marketing for multiple recreational boating businesses and startups.
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