By Capt. Ted Lund

Gasoline is probably one of the most important parts of an outboard owner’s day. Not only will outboards not run without it, but the type of fuel you run can also affect your engines’ performance, fuel efficiency and lifespan. Using E-15 — also known as high ethanol fuel — can cause serious damage to your engine and void the warranty on your high-dollar investment.

MAINTENANCE MATTERS: Beware E-15 Fuel  Gasoline is probably one of the most important parts of an outboard owner’s day. Not only will outboards not run

The main culprit? Ethanol (corn alcohol additives) intended to lower emissions and boost octane in fuel. Leading marine manufacturers like Yamaha Outboards recommend running non-ethanol fuel, with tolerances of up to E-10. New government regulations, however, are allowing for the sale of high-ethanol fuel, which contains nearly 50-percent more ethanol than E-10. And that will cause serious problems for boaters.

Mixing ethanol with fuel isn’t a new concept. In fact, Henry Ford’s Model T, first released in 1906, was designed to run entirely on ethanol, leaded gasoline or a mixture of both.

 During the 1920s, the US government started experimenting with adding ethanol (mostly derived from corn) as an octane booster. With fuel rationing becoming necessary during WW II, ethanol became even more important.

After the war, interest in ethanol faded due to the inexpensive cost and abundance of leaded fuel. In the 1970s, however, as availability dropped and more focus was placed on cleaner emissions standards, ethanol again grew in popularity.

By the late 1980s, engine manufacturers like Yamaha began modifying their engines to allow for some ethanol fuel usage, capped at E-10. But the recent decision to allow high ethanol blends could cause problems for boat owners and their equipment.

High ethanol fuel is often less expensive and either poorly marked or sold from pumps right next E-10. Not paying attention could lead to a very expensive mistake.

But why is high ethanol fuel a potential threat for boaters? As previously mentioned, high ethanol fuel can contain up to 50% more ethanol than E-10 fuels. The higher ethanol content increases the risk of phase separation, where the ethanol absorbs water and separates — leaving two different layers in your fuel tank — and leading to a multitude of issues.

At about the time ethanol was becoming popular in the 1970s, many boat manufacturers were looking at alternative fuel cells for boats. Traditional aluminum tanks were susceptible to corrosion and eventually cracking. Some started looking towards fiberglass, allowing them to customize the size and shapes of tanks in-house. Unfortunately, ethanol is a powerful solvent, and the concentrations found in high ethanol blends causes fiberglass resin to dissolve and suspend in the fuel tank, eventually leading to engine failure.

Fuel lines also had similar problems, often introducing contaminants into the engine while running, causing it to bog down or lock up.

But there are some precautions boaters can take, even with E-10 fuel to get the most out of their engines.

Ethanol shortens the shelf life of gasoline, and older fuel is more likely to absorb water and cause problems. For that reason, it is recommended that boaters not use ethanol fuel over 90 days old.

Keep a regular maintenance schedule, changing fuel filters and keeping carburetors clean to help limit or eliminate sludge build up that can affect performance or cause permanent damage.

Keep on top of repetitive issues. Don’t hesitate to address problems immediately. If carburetors are constantly fouling, drain the fuel and replace it with fresh fuel.

In an ideal world, the best solution is to use non-ethanol fuel, available at most marinas and a number of gas stations. Although the cost may be higher in the short term, your long-term investment will be protected.

But, what do you do when ethanol-free isn’t available? Yamaha’s award-winning team of engineers, designers and chemists have created a whole line of lubricants and additive to help combat the cumulative effects of ethanol-blended products.

All Yamalube ® marine lubricants and additives have achieved NMMA® (National Marine Manufacturer’s Association) FC-W® or TC-W3® certification. Oils that earn NMMA certification have passed rigorous testing, and have been proven to provide the performance and protection demanded by today’s advanced outboard technology. These oils stand up to the extended full-throttle operation, high loads and the salt and moisture-rich air found in a harsh marine environment. Boaters can also find additives like Yamahalube Fuel Stabilizer and Additive Plus and additive or Ring Free Plus specifically formulated to combat wear and tear caused by ethanol-blended fuels.

For more information on how to take care of your Yamaha Outboard motor, helpful fishing tips or more information on the 2019 Yamaha lineup of outboard engines, visit

And remember, when it comes to performance, Maintenance Matters.

Original Source: Sportsmans



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