Join Date: Sep 2011
Thanked 214 Times in 155 Posts
Ethanol-free is all I use in my cycles and small engines.
For those that aren't familiar with the issues created by ethanol in gasoline, there's a ton of info out there.
Basically, ethanol is corrosive and contains/holds water and will attack seals and some gaskets in older (pre-ethanol) engines. Because it contains/holds water, it increases the chances of rust forming in a steel gas tank.
Blending ethanol into gasoline reduces its energy, so more is required to reach an optimum air'fuel ratio. That's why you get worse mileage with ethanol-blended gas. In an engine with a carb, you get a leaner mixture which will reduce power and can cause engine damage.
There's more to it, but that's the basics. Really nothing good about blending ethanol with gasoline. I suggest avoiding it if possible.