Introduction: Nashville’s Dependence on Small Engines

From the rolling lawns of Green Hills to the compact lots in East Nashville, small engines power the lawnmowers, string trimmers, chainsaws, and leaf blowers that keep Music City looking its best. Whether you’re a homeowner maintaining your yard or a landscaping professional managing multiple properties, the reliability of your equipment is critical. In recent years, a quiet but persistent issue has emerged: the impact of ethanol-blended fuels on these machines. While ethanol has been promoted as a cleaner-burning additive, its effects on small engines, which are not designed for high-ethanol fuel, can be costly and frustrating. This article explores the science behind ethanol blends, their specific effects on small engines, and practical solutions for Nashville residents who want to keep their equipment running smoothly year after year.

What Are Ethanol Blends?

Ethanol is an alcohol fuel made from renewable plant materials—primarily corn in the United States. It is blended with gasoline to create fuels such as E10 (10% ethanol, 90% gasoline), E15 (15% ethanol), and E85 (85% ethanol). The most common blend available at Nashville gas stations is E10, which is used by millions of vehicles and small engines every day. The U.S. Environmental Protection Agency (EPA) has approved E10 for use in all conventional gasoline engines, but small engine manufacturers often warn against using blends higher than E10.

The rationale behind ethanol blending is partly environmental and partly economic. Ethanol reduces tailpipe emissions of carbon monoxide and other pollutants, and it extends the supply of petroleum. However, ethanol’s hygroscopic nature—its tendency to attract and absorb water—creates unique challenges for engines that are not sealed and may sit unused for weeks or months. According to the EPA’s Renewable Fuel Standard program, ethanol use has grown significantly over the past two decades, making it nearly impossible to find pure gasoline at the pump in many areas, including Middle Tennessee.

How Ethanol Affects Small Engines

Small engines in lawnmowers, chainsaws, trimmers, and generators are fundamentally different from automotive engines. They typically use carburetors rather than fuel injection, have simpler fuel systems, and are often made from materials that are less resistant to ethanol’s corrosive properties. When ethanol-blended fuel is used in these engines, several problems can arise.

Phase Separation

Phase separation is one of the most serious issues caused by ethanol. Because ethanol attracts moisture from the air, water can accumulate in the fuel tank over time. Once the water content reaches a certain threshold, the ethanol binds with the water and separates from the gasoline, forming two distinct layers. The bottom layer is a watery ethanol mixture that can be highly corrosive and can cause the engine to stall or refuse to start. This is especially problematic for equipment that is stored for long periods—like a lawnmower over the winter in Nashville’s humid climate. Even a small amount of phase separation can clog jets and passages in the carburetor, requiring expensive cleaning or replacement.

Corrosion and Material Degradation

Ethanol is a solvent and can dissolve certain rubber, plastic, and fiberglass components found in older small engines. Fuel lines, gaskets, and seals may swell, soften, or crack when exposed to ethanol, leading to leaks and vacuum loss. Aluminum carburetors can also suffer from oxidation and pitting when exposed to ethanol blends, especially if water is present. Many small engine manufacturers have updated materials in newer models, but thousands of Nashville residents still use older machines that are vulnerable. The Outdoor Power Equipment Institute (OPEI) recommends checking your owner’s manual for ethanol compatibility—most equipment built before 2012 is at higher risk.

Performance Issues

Even when phase separation hasn’t occurred, ethanol can cause performance problems such as hard starting, rough idling, and stalling under load. The lower energy density of ethanol means that engines may produce slightly less power, although this difference is minimal at E10 levels. More noticeable is the tendency for ethanol to evaporate more quickly than gasoline, leaving behind gum and varnish deposits in the carburetor. This is why equipment that sits unused for more than a month often fails to start—the fuel has degraded, not just gone stale.

The Nashville Factor: Climate and Usage Patterns

Nashville’s climate is characterized by hot, humid summers and mild to cool winters. Humidity is a key factor in ethanol-related problems because moist air accelerates the water absorption process. A lawnmower stored in an uninsulated shed during July can experience significant daily temperature swings, causing condensation to form inside the fuel tank. This water then gets absorbed by the ethanol, amplifying the risk of phase separation.

Humidity and Temperature

During the summer months, Nashville’s relative humidity often exceeds 70%. Small engines left outside or in damp garages are exposed to that moisture. When the temperature drops at night, condensation forms on the inside of the fuel tank. Ethanol acts like a sponge, pulling that water into the fuel. Over a period of weeks, the water content can rise enough to trigger separation. Using a fuel stabilizer that contains water-absorbing additives can help, but it’s not a complete solution. Many local lawn care professionals drain their tanks if equipment will sit for more than a couple of weeks.

Seasonal Storage

Nashville residents typically store their lawn equipment from November through March. That’s three to five months of potential fuel degradation. If the tank is left full of E10, the likelihood of phase separation and carburetor clogging is high. Following proper end-of-season storage procedures is essential for avoiding springtime repairs. The Fuel & Friction website provides a map of ethanol-free gas stations in the Nashville area, which can be a valuable resource for those who want to run pure gasoline during storage.

Best Practices for Nashville Residents

Despite the challenges, small engines can run reliably on ethanol blends if you adopt the right habits. Here are actionable recommendations for homeowners and professionals alike.

Fuel Selection

Always use fresh fuel. Purchase only what you will use within 30 days. If possible, buy ethanol-free gasoline for your small engines. Several gas stations in the Nashville metro area offer ethanol-free premium (90 octane or higher). These include certain Shell and Exxon stations, as well as smaller independent retailers. Using ethanol-free fuel eliminates the moisture and corrosion issues entirely. If you must use E10, consider adding an ethanol-specific fuel stabilizer like Sta-Bil Storage or Seafoam. These products help prevent phase separation and protect against corrosion.

Storage and Stabilization

For equipment that is used weekly, fuel stabilizer is less critical. But for any engine that will sit for more than two weeks, add stabilizer according to the manufacturer’s instructions and run the engine for a few minutes to circulate treated fuel throughout the system. At the end of the season, you have two good options: (1) run the engine dry by disconnecting the fuel line and letting it idle until it stops, or (2) fill the tank completely with treated fuel to minimize air space and condensation. For carbureted engines, draining the carburetor float bowl is also recommended. Many newer lawnmowers have a drain screw for this purpose.

Seasonal Maintenance

Before storing equipment for the winter, change the oil, clean or replace the spark plug, and inspect the air filter. These tasks ensure that the engine is in top condition and will start easily when you bring it out again. In the spring, before the first use, drain any old fuel and refill with fresh gasoline. If the machine was stored with stabilized fuel and the tank was full, it will usually start without issues. If you suspect phase separation (cloudy or layered fuel), drain the tank completely and clean the carburetor before attempting to start.

Alternatives to Ethanol-Blended Fuels

For those who want to completely avoid ethanol’s negative effects, there are several viable alternatives.

Premium Rec Fuel

Alkylate gasoline, sold under brand names like Aspen and TruFuel, is a synthetic fuel that contains no ethanol. It is pre-mixed for two-stroke engines (e.g., 50:1) or available in pure form for four-stroke engines. These fuels are stable for years, produce fewer emissions, and won’t harm rubber or plastic components. The only downside is the cost—typically $5–$8 per quart, making it impractical for large mowers but excellent for chainsaws, trimmers, and leaf blowers that are used infrequently.

Ethanol-Free Gas Stations

As mentioned, ethanol-free gasoline is available at select stations around Nashville. Websites like Pure Gas maintain an updated list. Pricing is usually higher than regular E10, but you avoid the long-term damage and downtime. For someone with several pieces of equipment, buying a 5-gallon can of ethanol-free gas every few months can be a cost-effective way to protect their investment.

Propane Conversion

Another alternative is converting small engines to run on propane. Propane burns cleaner, has no ethanol issues, and stores indefinitely. Kits are available for lawnmowers, generators, and pressure washers. The conversion cost can be several hundred dollars, but if you have a large operation, the fuel cost savings and reduced maintenance can pay off over time. However, propane is not as widely available for refilling in Nashville as gasoline, and you lose some power (about 10%) compared to gasoline.

Conclusion

Ethanol blends are a reality for Nashville residents, and they are unlikely to disappear anytime soon. While they offer environmental benefits and lower prices at the pump, small engine owners must adapt their maintenance practices to avoid costly repairs. By understanding how ethanol affects fuel systems, using stabilizers, choosing ethanol-free gas when possible, and following seasonal storage procedures, you can keep your lawnmower, chainsaw, and trimmer running reliably for years. Whether you are a weekend warrior or a seasoned landscaper, protecting your equipment begins with the fuel you put in it. Take the time to manage your fuel properly, and your small engines will reward you with dependable performance every time you need them.