What is the maximum ethanol content recommended for small engines?

E10, which contains 10 percent ethanol, is the maximum ethanol content recommended for most small engines. This level of ethanol is widely accepted because it provides a balance between performance and fuel stability while still complying with many manufacturers' guidelines. Ethanol can attract moisture and, at higher concentrations, can lead to issues such as corrosion, phase separation, and fuel system clogging, which can be particularly damaging to small engines.

Using E10 is often considered safe for small engines, as well as for a wide variety of other vehicles and equipment. Many manufacturers specify that E10 is compatible with their products and that it won't void warranties when used as directed. Higher concentrations of ethanol, such as E15 or E20, can increase the risk of engine damage, particularly in older engines or those not specifically designed for higher ethanol blends. Therefore, E10 is recommended to ensure the longevity and reliability of small engine systems.