What is the maximum ethanol rating that small engine manufacturers currently recommend for fuel?

Small engine manufacturers typically recommend a maximum ethanol rating of E10, which contains 10% ethanol and 90% gasoline. This recommendation is based on the understanding that while small engines can tolerate some ethanol in their fuel, higher concentrations can lead to problems such as fuel system corrosion, phase separation, decreased performance, and increased wear on engine components.

E10 is often seen as a safe compromise that helps reduce carbon emissions without significantly impacting engine performance or reliability. At the same time, pure gasoline with 0% alcohol can be challenging to find in many areas due to the increased use of ethanol-blended fuels in the market. Higher ethanol blends, such as E15 or E85, pose a greater risk for small engines, leading manufacturers to caution against their use to avoid potential engine damage and operational issues.