What Type of Gas to Use in a Lawn Mower?

When it comes to keeping your lawn mower running smoothly and efficiently, choosing the right type of gas is essential. Lawn mowers are typically powered by gasoline engines, and using the wrong type of fuel can cause performance issues or even damage the engine. Here’s a detailed guide on what kind of gas you should use in your lawn mower to ensure optimal performance and longevity.

1. Unleaded Gasoline

Most lawn mowers are designed to run on regular unleaded gasoline. Specifically, it’s best to use gasoline with an octane rating of 87 or higher. This is typically regular-grade fuel found at most gas stations. Higher-octane fuels are usually unnecessary for lawn mowers and may not provide any additional benefits.

2. Avoid Gasoline with High Ethanol Content

While ethanol-blended fuels are common, it’s crucial to avoid gasoline with more than 10% ethanol (commonly labeled as E10). Ethanol can attract moisture, which may lead to corrosion in the fuel system over time, especially in small engines like those in lawn mowers. Fuels labeled as E15 or E85 (which have higher ethanol content) should never be used in lawn mowers, as they can cause serious engine damage.

3. Premium Gasoline: Is It Necessary?

Premium gasoline with a higher octane rating (above 87) is not required for most lawn mowers. While some people believe premium fuel may boost performance or engine life, there’s little evidence to support this for typical lawn mower engines. Using regular unleaded gas is usually sufficient unless the manufacturer specifically recommends premium fuel.

4. Fuel Stabilizers for Longevity

If you don’t use your lawn mower frequently or plan to store it for an extended period, consider adding a fuel stabilizer to the gas tank. Fuel stabilizers prevent the gasoline from breaking down and causing gum or varnish buildup in the engine. This can help extend the lifespan of your lawn mower and avoid issues when restarting the engine after storage.

5. Fresh Gasoline Is Key

Small engines are more sensitive to stale fuel than larger ones. Always try to use fresh gasoline (less than 30 days old) in your lawn mower to prevent starting problems and engine knocking. If you have old gas, it’s best to drain it from the mower and replace it with fresh fuel.

6. Two-Stroke vs. Four-Stroke Engines

  • Two-Stroke Engines: Some older or smaller lawn mowers may have two-stroke engines, which require a mix of gasoline and two-stroke oil. It’s important to follow the manufacturer’s specific fuel-to-oil ratio when mixing fuel for these types of engines.
  • Four-Stroke Engines: Most modern lawn mowers use four-stroke engines, which require only gasoline and have a separate oil reservoir. Be sure to fill the oil and gasoline separately, as using oil in the gas tank of a four-stroke engine can damage it.

Conclusion

For most lawn mowers, regular unleaded gasoline with an octane rating of 87 is the best choice. Avoid high-ethanol fuels, and consider using a fuel stabilizer if you’re storing the mower for a long period. If your lawn mower uses a two-stroke engine, ensure you’re using the correct fuel-to-oil mix. By following these guidelines, you’ll keep your lawn mower running smoothly for years to come.

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