Why Gasoline With More Than 10% Ethanol Will Make Your Mower Sad

Modern cars are designed to get around just fine with gasoline containing ethanol in their tanks, but not all gasoline that you buy at the corner gas station is healthy for other items that you own that use gas. Think outdoor power equipment like push mowers, string trimmers, and chainsaws. Cars made in 2006 and afterwards can take fuel that’s up to 15% ethanol, but that mixture can be disastrous for small gas-powered appliances.

There’s a trade group for these items, the Outdoor Power Equipment Institute, and they are not happy that higher-ethanol blends are becoming more common in gas stations, but lack consumer warnings at the pump that explain this clearly. Something like “Hey dude/dudette, don’t put this stuff in your chainsaw,” it might say, but most consumers say that they don’t notice the puny warnings that the EPA requires.

Why shouldn’t you use these cheaper blends in your outdoor power equipment? Since you probably don’t use your lawn mower as often as your car, all of that time sitting around idle means that the ethanol has time to draw water from the gasoline, making the fuel goopy and crusty, which hurts any plastic and rubber parts that it reaches as well as affecting carburetors. Worse, ethanol makes small engines run hotter, reducing their lifespan.

You can prevent this by checking what kind of fuel your small gas-powered equipment prefers: that information should be in the manual. Don’t automatically fill your gas can with the same stuff you put in your tank, especially if your car is much newer than average.

The cheapest gas can be trouble for outdoor gear [Consumer Reports]