It is perfectly safe to used ethanol-blended fuel (E10) in your lawn mower and other equipment powered by a small engine.

This post was updated in March 2022.

As many readers probably know, most gasoline sold in the U.S. contains 10% ethanol and Minnesota law requires nearly all gasoline sold in the state to be E10. Blending ethanol in our fuel supply helps improve air quality and reduces America’s dependence on foreign oil. Despite myths to the contrary, E10 blends are safe to use in your lawn mowers, chain saws and other equipment powered by small engines.

Below are some common myths about E10 and small engines and facts to dispel them.

Myth: E10 has a short shelf life.

Fact: The minimum shelf life of E10 is six months. It may even last longer than one year under proper storage conditions. Prevent air and water from entering the tank using the tips below.

Myth: Ethanol in fuel absorbs humidity and leads to excess water in a lawn mower’s fuel tank.

Fact: Water in fuel occurs when it condenses out of the air inside the fuel tank when the air temperature drops. Straight gasoline can absorb up to 300 parts-per-million (ppm) of water before free water will form, which can cause engine damage. E10 can absorb up to 5000 ppm before free water will form. This allows E10 to pull the moisture through and out of the system as the fuel is used, so the chance for having free water in your fuel tank with E10 is extremely low. To prevent air and moisture, keep fuel and equipment tanks full when not in use and seal tightly.

Myth: Ethanol separates from gasoline in the fuel tank.

Fact: Ethanol blends completely with gasoline and will not separate. The only time ethanol and gasoline will separate is in the presence of a high amount of water. This is an unusual circumstance and occurs when water percentage exceeds 0.5% (5000 ppm). This will only happen when proper housekeeping practices are not followed.

Myth: Ethanol causes damage to equipment components.

Fact: A 10% ethanol blend is found in more than 95% of gasoline sold in the U.S. today. Small engine manufacturers develop products with the proper components to run on E10, as indicated by their statements permitting its use.

When you’re done using your equipment for the season:

• If only a small amount of fuel remains, run the engine until completely empty before storing.
• If substantial fuel remains in the tank, fill the tank full and seal with an airtight cap to prevent air from entering.
• If you do not completely fill or empty the tank, use a fuel stabilizer, running the engine briefly to allow the stabilizer to reach the entire fuel system.

There is no need to spend extra money on “premium” fuel that doesn’t contain ethanol.  You can save money and choose a cleaner, more renewable, Minnesota-made fuel blend simply by choosing E10 for your small engines.

Written by Hoon Ge, founder of MEG Corp, a leading fuel consulting company based in Plymouth. Ge is a chemical engineer with over 35 years of experience in the petroleum industry, including refining, additive formulation and alternative fuels.

As part of its mission to maintain and develop markets for corn and corn co-products, Minnesota Corn is proud to support efforts to promote homegrown, cleaner-burning biofuels. Visit mncorn.org to learn about the many ways Minnesota Corn is supporting ethanol in the state. Information about the many benefits of ethanol-blended fuels and where you can find them is at betterfuel.org.