Fresh gasoline is more volatile than stale gasoline. Gasoline over 30 days old has likely lost volatility and is unsuitable for use in most smaller engines on outdoor power equipment. If storing a piece of equipment for more than 30 days, drain or run out any gasoline which remains in the fuel system (tank, fuel lines, carburetor(s), etc.).

When gasoline becomes old and stale, it begins to break down and become what is commonly called engine gum, or engine varnish. This gum or varnish is detrimental to the fuel delivery system and more specifically the carburetor of an engine. It can build up and cause clogs. If this happens, fuel travel through the engine can decrease or altogether stop.

There is one option which allows gasoline to store for a prolonged period. Gasoline stabilizer can be found at retailers that sell outdoor power equipment, some hardware, and most auto parts stores. This product must be mixed with gasoline the day of a fuel purchase. Mixed properly, it can extend the life of fuels. For best results when using gasoline stabilizers, please follow the exact directions found on the container of the stabilizer product as prescribed by the stabilizer manufacturer.