The effects of using ethanol-blended gasoline are well documented when it concerns a medium-to-large engine like that of your car or boat.
Ethanol Issues in Small Engines
When it comes to small engines like your lawnmower, filling them with ethanol fuel can be just as hazardous, if not more. That's because you're likely not starting and using your lawnmower every day, so the fuel is always there to sit in the tank. This leads to a bevy of problems.
- Ethanol-blended fuels are known to absorb water if they sit unused for periods of time. This makes it harder to start small engines like lawnmowers.
- Ethanol is corrosive (in part, because of its water-absorbing power), so small engine parts may become easily damaged.
- Ethanol burns hotter, which can lead to overheating and other engine problems.
- The water absorbed by ethanol-gas interfere with the two-cycle oil in the fuel, preventing proper lubrication and raising the real chance of engine damage.
So just as it is with large engines, it's important to use ethanol free gas or administer a fuel additive to small engines as well.
E15 Gasoline – Not Legal for Small Engines
Another wrinkle is that, if you’re in an area where E15 fuel is available (and those areas are growing), you can’t put E15 in your lawnmower. E15 is not approved for use in many types of engines, so filling up your lawnmower with it is technically illegal. Not to mention that the higher amount of ethanol in the fuel will accelerate all of the problems mentioned above.
Ethanol-Free Gas or Additive?
The two main options for preserving the life of your small engine are either to refrain from using ethanol-blended gas or to administer a fuel additive to essentially wipe the ill-effects of the ethanol in the fuel mixture. While the former option is ideal, it's not always practical - as finding a gas station that sells only ethanol-free gas can be a real chore. So a fuel treatment may become the only feasible option. They're inexpensive and should work to stabilize the fuel mixture and control water absorption without using alcohol in their formulation.
Administering a fuel additive or using ethanol free gas can pay off big time.
This post was published on June 6, 2014 and was updated on November 6, 2019.