[DisillusionedPrepper]

The fact is there are two issues with Ethanol based fuels. First, and foremost it is hygroscopic. It attracts water from it's environment. Being that gasoline, and water have no molecular attraction the water in the ethanol is forced out of suspension, and settles to the bottom. That is where our fuel is drawn from in most applications so as you can guess...

Secondly ETOH is a very active solvent. It attacks everything from binders (glues/adhesives) to metals. Now oddly enough it has NO effect on rubber. What it does is dissolve the binders between rubber/paper (gaskets) rubber/plastics (fuel lines), even rubber and Teflon. Teflon is used in many fuel lines, and that thin wall of Teflon inside the fuel line will separate from the rubber casing, and collapse. This blocks the fuel flow, and leads to lean running conditions that can destroy an engine in short order.

10 years ago ETOH fuel was a menace. 5 years ago it was still a big issue. Today it should be a non issue as most gaskets, and fuel lines are made ETOH proof. The only remaining issue is age. As that fuel sits it absorbs more, and more water. The gas releases that water from the ETOH so the ETOH never becomes saturated, and the process continues.

I have a firm rule I stick to. If my fuel is not used within 3 months I will drain it, and toss it. You can used additives to "save" fuel but I'm not in that school. I've made a living out of repairing engines, and I don't need or want to repair my own (if that can be avoided).

If you are storing an engine (winter), drain the fuel completely, run the carb/injection system dry. There are further steps you can/should take to storing an engine but for the majority of us a dry system is better than ethanol fuel sitting in it.