Ethanol-Free Gas: What It Is and Does Your Small Engine Need It?
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Key Takeaways
- All 14 small engine and equipment brands we checked allow gas with up to 10% ethanol (E10). None of them requires ethanol-free gas.
- E15 is banned by federal law in lawn mowers, chainsaws and other outdoor power equipment.
- In Department of Energy testing, small engines ran 10°C to 50°C hotter on E15 than on ethanol-free gas.
- E10 can hold only about 0.5% water at 60°F before the ethanol and water separate from the gas.
- Ethanol-free gas is worth it for equipment that sits for months, 2-stroke tools and older engines. For a mower you use every week, fresh E10 is fine.
Ethanol-free gas costs more than regular gas. So is it worth paying extra for your mower, generator or chainsaw?
Most advice online says yes, always. The owner’s manuals tell a more useful story.
We checked the fuel requirements of 14 small engine and equipment brands. We also went through EPA rules and Department of Energy test data.
This article covers what ethanol-free gas is, what manufacturers actually require, and when ethanol-free gas is worth the money.
What Is Ethanol-Free Gas?
Ethanol-free gas is gasoline with no ethanol blended in. You’ll also see it called E0, pure gas or non-ethanol gas.
At the pump, it’s often sold as “REC-90,” short for recreational fuel at about 90 octane. REC-90 is a marketing name, not an official grade.
We found no definition of it from the EPA or ASTM. The ASTM D4814 gasoline standard doesn’t set the amount of ethanol in gas at all.
How Common Is Ethanol-Free Gas?
Not very. Most gasoline sold in the U.S. is about 10% ethanol, according to the U.S. Energy Information Administration (EIA).
In 2015, E10 made up more than 95% of the gas used by vehicles. The latest national figure we could find for ethanol-free gas is from 2014, when it was just under 7% of gasoline demand.
| Fuel | Ethanol | OK for small engines? |
|---|---|---|
| E0 (ethanol-free, often “REC-90”) | 0% | Yes |
| E10 (regular pump gas) | Up to 10% | Yes, by all 14 brands we checked |
| E15 | Up to 15% | No. Banned in outdoor power equipment |
| E85 (flex fuel) | 51% to 83% | No |
Do Small Engines Need Ethanol-Free Gas?
No. Every manufacturer we checked approves regular E10 gas. None of them requires ethanol-free gas.
We pulled the fuel rules from the owner’s manuals and official support pages of 14 brands. Here’s what each one says.
| Brand | Max ethanol | Min octane | Storage advice |
|---|---|---|---|
| Honda | 10% | 86 | Under 1 month: nothing needed. 1–2 months: add stabilizer. Up to a year: stabilizer and drain the carburetor bowl. Over a year: drain everything. |
| Briggs & Stratton | 10% | 87 | Always use stabilizer. Drain untreated fuel. Buy only 30 days’ worth. |
| Kohler | 10% | 87 | Unused 2+ months: add fuel treatment and run 2–3 minutes. |
| Kawasaki | 10% | 87 | Stored over 30 days: drain the fuel completely. |
| STIHL | 10% | 89 | Stored over 30 days: store dry. Use mixed fuel within 60 days. |
| Husqvarna (chainsaws) | 10% | 87 | Not listed on the support page. |
| ECHO | 10% | 89 | Use gas bought within the last 30 days. |
| Toro | 10% | 87 | Add stabilizer the day you buy fuel. Buy 30 days’ worth. |
| Cub Cadet | As low as possible | Not listed | Stabilizer at the start and end of each season. |
| Generac (portable) | 10% | 87 | Treated fuel can stay in. Drain untreated fuel. |
| Champion | 10% | 87 | Stabilizer covers up to a year. Longer: drain tank and carburetor. |
| Predator | 10% | 87 | Stabilizer is required to keep the warranty. |
| Yamaha (generators) | 10% | 86 | Long-term: drain the tank and carburetor. |
| Westinghouse | Under 10% | 87–93 | Stabilized fuel up to 6 months with the carburetor bowl drained. |
Three things stand out.
First, E10 is the limit for every brand. Briggs & Stratton, Kohler, Toro, Cub Cadet, Champion and Predator all name E15 as not approved.
Second, no brand requires ethanol-free gas. Cub Cadet and Toro clearly prefer it, though, and STIHL sells its own ethanol-free fuel.
Third, brands disagree on storage. Some say to add stabilizer and leave the fuel in. Others say to drain it.
That’s why your own manual matters more than general advice.
Warranty warning: Honda, Briggs & Stratton, Toro and STIHL say damage from fuel with more than 10% ethanol may not be covered. Champion’s manual goes further and excludes damage caused by ethanol-blended gas in general.
Can You Use E15 in Small Engines?
No. Using E15 in small engines is against federal law.
The EPA bans E15 in engines like “lawnmowers and chain saws,” as well as in boats, snowmobiles and motorcycles.
Pumps that sell E15 must carry an orange-and-black EPA warning label. Here’s the label text from the original rule:
“Attention. E15. Up to 15% ethanol. Use only in 2001 and newer passenger vehicles and flex-fuel vehicles. Don’t use in other vehicles, boats, or gasoline-powered equipment. It may cause damage and is prohibited by Federal law.”
EPA E15 label, as shown in an EPA-hosted model misfueling plan
Is E15 Getting Easier to Find?
Yes. In 2026, the EPA issued a series of emergency waivers that let stations sell E15 through the summer.
In May 2026, the House passed a bill to allow E15 year-round. In September, a Senate committee moved a farm bill with a similar provision. As of November 2026, it isn’t law.
Either way, read the pump label every time. Some stations sell E10 and E15 from the same hose.
What Happens When You Run a Small Engine on E15?
The U.S. Department of Energy tested this. In 2009, two national labs ran 28 small engines on E0, E10, E15 and E20.
Here’s what they found:
- The engines ran hotter. Exhaust temperatures rose 10°C to 50°C from E0 to E15. Going from E10 to E15 alone added 5°C to 10°C.
- Some trimmers engaged on their own. Three handheld trimmers idled faster on ethanol blends, enough for the cutting head to spin without the throttle. That’s a safety risk.
- Idling got rough. One generator ran unevenly at idle on E20, and one blower wouldn’t idle at all.
Most owners never check. In a 2019 survey for the Outdoor Power Equipment Institute, only 20% of Americans said they notice ethanol content at the pump.
How Does Ethanol Affect Small Engines?
Ethanol works fine in a car that burns a tank of gas every week. Small engines are different.
They often sit for months. Most use a simple carburetor. And the fuel may have been in a gas can since last season.
Here’s where ethanol causes trouble.
1. Ethanol Holds More Water Than Gas
Gasoline is made of hydrocarbons, which don’t mix with water. Ethanol is an alcohol, and small alcohols like ethanol dissolve completely in water.
So adding ethanol to gas lets the fuel hold more water. But only up to a point.
The EPA puts that limit at about 0.5% water for E10 at 60°F. That’s about 3.8 teaspoons per gallon. Gas without ethanol holds only about 0.15 teaspoons.
Chevron’s technical review shows the same gap in parts per million. Regular gas holds about 150 ppm of water at 70°F. E10 holds 6,000 to 7,000 ppm.
2. E10 Can Phase Separate
When E10 takes on more water than it can hold, it splits into two layers. This is called phase separation.
A layer of water and ethanol sinks to the bottom of the tank. According to Chevron, it can pull up to 90% of the ethanol with it.
The gas left on top has a lower octane rating. And an engine won’t run on the bottom layer at all.
In a 2-stroke engine, it’s worse. The EPA notes that the water-ethanol layer competes with the mixed-in oil, so the engine may not get enough lubrication.
A fuel stabilizer won’t fix this, because stabilizers only slow down oxidation.
BoatUS advises that phase separation can only be fully prevented by emptying the tank. Separated fuel should be drained and disposed of properly.
3. Ethanol Makes the Engine Run Leaner and Hotter
Ethanol is about 35% oxygen by weight. It needs much less air to burn: an air-fuel ratio of about 9:1, compared with 14.7:1 for gas, according to the Department of Energy’s ethanol handbook.
A car’s computer adjusts for this. A basic small engine carburetor can’t. The DOE’s small engine report says these engines can’t compensate for ethanol, so they run leaner and hotter.
Ethanol also has less energy. The DOE lists 76,330 Btu per gallon for ethanol versus 112,114 to 116,090 for gasoline.
The EIA estimates fuel economy drops about 3% on E10. For a generator, that means a little less run time per tank.
4. Ethanol Can Affect Older Fuel Lines and Seals
Ethanol is a stronger solvent than gas. Testing at Oak Ridge National Laboratory found that common rubber seals swell the most at around 17% to 25% ethanol. Metal corrosion was very low overall.
Chevron notes that rubber parts in much older equipment, built before ethanol blends were common, may not hold up as well.
Many owners on repair forums report hardened primer bulbs and cracked fuel lines that they blame on E10. Others report years of trouble-free use.
These are personal reports, not test results. But they fit the research: problems show up most in old parts and stored fuel.
Does E10 Absorb Water From the Air?
Not enough to cause phase separation on its own. This is one of the most repeated myths about ethanol.
The EPA’s analysis found that phase separation won’t happen if the only water source is the air, as long as the temperature stays the same. It takes liquid water getting in, or water condensing as the fuel cools.
Storage tests point to a bigger problem: gas going stale.
- Sealed cans held up well. In an Oak Ridge National Laboratory study, regular E10 sealed in cans stayed within fuel specifications for at least 12 months, with no stabilizer.
- Vented tanks went stale. In a 2016 study of fuel in vented mower tanks, the gas lost octane and formed gum. Some tanks lost 30% to 70% of their fuel within months. The study was paid for by the Renewable Fuels Association, an ethanol trade group.
So how you store fuel matters as much as whether it has ethanol. A vented tank or a full carburetor bowl left for months is where any gas breaks down.
Ethanol-free gas removes the risk of phase separation. It still goes stale, though, so storage habits still count.
Is Ethanol-Free Gas Better for Small Engines?
Yes, for engines that sit. For engines you use every week, the difference is small.
| Your equipment | Best fuel | Why |
|---|---|---|
| Standby or emergency generator | Ethanol-free gas plus stabilizer | It sits for months, then has to start right away. |
| Snowblower or other one-season equipment | Ethanol-free gas, at least for the last tank before storage | Long storage through big temperature swings. |
| 2-stroke chainsaw, trimmer or blower | Ethanol-free gas or ethanol-free premix | STIHL limits mixed fuel to 60 days unless it’s ethanol-free premix. |
| Older or vintage equipment | Ethanol-free gas | Older rubber parts may not handle ethanol well. |
| Mower used every week in season | Fresh E10 is fine | The fuel gets used within weeks. |
| Any small engine | Never E15 or higher | Banned by federal law and runs hotter in tests. |
How Much More Does Ethanol-Free Gas Cost?
Ethanol-free gas usually costs 20 cents to $1 more per gallon than E10, depending on where you live.
Small engines don’t use much fuel. If you burn 10 gallons a season, that’s an extra $2 to $10 a year by our math. One carburetor cleaning usually costs more.
Where Can You Buy Ethanol-Free Gas?
You have two options: a gas station that sells it, or sealed cans of ready-to-use fuel.
Gas Stations
Pure-gas.org is a free, community-run map of stations that sell ethanol-free gas in the U.S. and Canada. It had over 12,000 listings by 2017, including about 1,000 marinas and airports.
Users add the listings, so some may be out of date. Call ahead before a long drive.
Availability also depends on your state. Minnesota, for example, requires most gas sold at retail to contain ethanol, with some exceptions.
Canned Ethanol-Free Fuel
Several brands sell sealed cans of ethanol-free fuel. At the list prices we checked, they cost roughly $25 to $30 per gallon.
That’s expensive. But they’re ready to use and last a long time, which makes sense for small handheld tools you use now and then.
| Product | Type | Octane | Shelf life (brand’s claim) |
|---|---|---|---|
| TruFuel | 4-cycle, 40:1 and 50:1 | 92+ | 5 years unopened, 2 years opened |
| STIHL MotoMix | 50:1 premix | 92 | STIHL’s pages give different figures. Check the can. |
| Husqvarna XP+ | 2-stroke premix | 95 | Not listed on the U.S. page |
| ECHO Red Armor | 50:1 premix | 93 | 5 years unopened, 2 years opened |
How to Store Gas for Small Engines
These steps work for both E10 and ethanol-free gas.
1. Check Your Owner’s Manual
It tells you the maximum ethanol, the minimum octane and whether to drain or stabilize before storage.
2. Buy Only What You’ll Use in 30 Days
Briggs & Stratton, ECHO and Toro all recommend this. Fresh fuel causes fewer problems.
3. Keep Gas Cans Sealed
Store them out of the sun, away from living spaces. Sealed E10 stayed in spec for a year in Oak Ridge testing.
4. Add Stabilizer When You Buy the Gas
If the fuel might sit, treat it right away. Then run the engine for a few minutes so the treated fuel reaches the carburetor.
5. Follow Your Manual’s Storage Rule
Some brands say drain the fuel. Others say stabilize and leave it in. Use ethanol-free gas for the last tank if you can.
6. Never Use E15
Read the pump label every time you fill a gas can.
Fuel Products That Meet These Recommendations
These products line up with the storage advice in this article. Check that any fuel matches the ethanol limit and octane in your manual.
| Product | Why it fits | Where to buy |
|---|---|---|
| STA-BIL Storage Fuel Stabilizer (22214, 32 oz) | The maker says it keeps fuel fresh up to 24 months at 1 oz per 2.5 gallons, for 2- and 4-cycle engines. | Check price on Amazon |
| STA-BIL 360 Protection (22275, 32 oz) | An ethanol treatment and stabilizer the maker rates for up to 12 months of storage. | Check price on Amazon |
| TruFuel 4-Cycle (6527238, 32 oz) | Ready-to-use ethanol-free fuel for 4-stroke engines. | Check price on Amazon |
| TruFuel 50:1 Premix (6525638) | Ethanol-free 50:1 premix for 2-stroke tools, made with JASO FD registered oil. | Check price on Amazon |
| ECHO Red Armor 50:1 Premix (7450001) | Ethanol-free, 93 octane premix. ECHO rates it for 2 years opened, 5 years unopened. | Check price on Amazon |
| No-Spill 1405 Gas Can (2.5 gal) | A sealed can the maker lists as CARB and EPA compliant, for storing fuel safely. | Check price on Amazon |
FAQs
Is ethanol-free gas the same as premium gas?
No. “Premium” only refers to octane. Most premium gas in the U.S. still contains up to 10% ethanol.
Does ethanol-free gas last longer?
It stores better because it can’t phase separate. It still goes stale over time, especially in vented tanks, so use a stabilizer for long storage.
Can you mix ethanol-free gas with regular gas?
Yes, it’s safe. The mix will contain some ethanol, so you lose part of the storage benefit.
Will a fuel stabilizer fix phase-separated gas?
No. Stabilizers slow oxidation, but they can’t reverse phase separation. Drain the fuel and dispose of it according to local rules.
Can I use E15 in my lawn mower?
No. E15 is banned in lawn mowers and other outdoor power equipment under federal rules, and no manufacturer approves it.
Conclusion
You don’t need ethanol-free gas for most small engines. Every manufacturer we checked approves E10.
But ethanol-free gas is the better choice for equipment that sits, like a standby generator or a snowblower. It’s also a smart pick for 2-stroke tools and older engines.
Whatever you use, store it well: keep cans sealed, add stabilizer, and follow your manual. And never put E15 in a small engine.
Mixing fuel for a chainsaw or trimmer? Use our 2-cycle oil mix calculator to get the oil amount right.
Sources
- U.S. Energy Information Administration. How much ethanol is in gasoline, and how does it affect fuel economy?
- U.S. Energy Information Administration. Almost all U.S. gasoline is blended with 10% ethanol, May 2016.
- Hydrocarbon Processing. U.S. demand rises for ethanol-free gasoline: API, May 2015.
- ASTM International. D4814, Standard Specification for Automotive Spark-Ignition Engine Fuel.
- Manufacturer fuel requirements: Honda, Honda EU2200i manual, Briggs & Stratton, Kohler, Kawasaki, STIHL, Husqvarna, ECHO, Toro, Cub Cadet, Generac, Champion, Predator (wording checked from search excerpts; direct access blocked), Yamaha, Westinghouse.
- 40 CFR § 1090.1510. E15 labeling provisions.
- U.S. EPA. E15 fuel registration.
- Renewable Fuels Association. Model E15 Misfueling Mitigation Plan, 2012 (hosted by EPA; industry document).
- U.S. EPA. Fuel waivers (2026 actions).
- KCUR. E15 bill passes U.S. House, May 2026.
- Grain Journal. Senate Agriculture Committee advances farm bill with year-round E15 provision, September 2026.
- Knoll, K., West, B., Clark, W., et al. Effects of Intermediate Ethanol Blends on Legacy Vehicles and Small Non-Road Engines, Report 1 – Updated. NREL and ORNL for the U.S. Department of Energy, 2009.
- Outdoor Power Equipment Institute and The Harris Poll. Confusion at the gas pump could be costing Americans dearly, March 2019 (industry survey).
- Korotney, D. Water Phase Separation in Oxygenated Gasoline. U.S. EPA, 1996.
- Chevron. Motor Gasolines Technical Review, 2009 (industry publication).
- Ball, D., Hill, J., and Scott, R. Physical Properties of Alcohols. LibreTexts.
- BoatUS. The Boater’s Guide to Winterizing (industry guidance).
- U.S. Department of Energy. Handbook for Handling, Storing, and Dispensing E85 and Other Ethanol-Gasoline Blends, 2016.
- U.S. Department of Energy, Alternative Fuels Data Center. Fuel properties comparison.
- Kass, M. D., Theiss, T. J., Janke, C. J., and Pawel, S. J. Compatibility Study for Plastic, Elastomeric, and Metallic Fueling Infrastructure Materials Exposed to Aggressive Formulations of Ethanol-blended Gasoline. ORNL/TM-2012/88, 2012.
- Sluder, C. S., and Davis, S. C. Assessment of the Effectiveness of Three Aftermarket Gasoline Fuel Stabilizers in Preventing Gum Formation and Loss of Oxidation Stability. SAE Technical Paper 2022-01-0486.
- Renewable Fuels Association. New DOE study: gas becomes stale long before water uptake becomes a concern, 2016 (summary of NREL report TSA 14-665; industry-funded).
- NACS Magazine. The pros and cons of ethanol-free gas, September 2025.
- Pure-Gas.org station directory, and Stillwater Associates, How much “ethanol-free” gasoline is out there?, 2017.
- Minnesota Statutes § 239.791. Oxygenated gasoline.
- Canned fuel product pages: TruFuel, STIHL MotoMix, Husqvarna XP, ECHO Red Armor.