Thread: gas prices
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Unread 04-28-2020, 02:51 PM   #563
Veteran DIYer- Schluterville Graduate

STAR Senior Contributor

Join Date: Jul 2004
Location: Nashua, NH
Posts: 14,382
Normally, other than the fact that there's less energy per gallon when you substitute some ethanol, you don't run into problems with using E10.

But, when you have something that doesn't have a sealed tank (all modern cars do), some of that ethanol WILL evaporate. On those things, like mowers, outboards, etc., when some ethanol evaporates, it will also pull in some outside air that will have some moisture in it. This CAN under some circumstances, do what is called phase separation where the alcohol, water, gasoline stratify. That can be a major problem. Normally, the alcohol will absorb small amounts of moisture and keep it dissolved in the fluid, and not be an issue.

For example, the airplane that I crashed had an engine that was designed for up to E10. But, the instructions said you should buy it fresh, and never leave it sit in the tank for longer than 2-weeks. Airplanes, and most small engines, will be vented to the atmosphere, so moisture and evaporation can be a real issue. Most airplane engines that use gasoline, run 100LL, which will have stabilizers and no ethanol in it. Mine could use the low lead stuff, but if you did, it required much shorter service intervals. It's nearly impossible to buy unleaded around here without it being E10, though. WHen on trips, when I could get it without, the car would get better MPG, though.

E10 was instituted when there was a fuel shortage and they wanted to stretch the supply. IMHO, using corn to make the stuff is a horrible thing...corn is particularly inefficient with regards to irrigation and fertilizer needs, and, using a foodstuff to make ethanol, except maye wiskey! seems like such a waste!

Some people I work with do small engine repair, and 99% of the problems they see are from people using E10 and then letting things sit, like in a mower, or snow blower, or outboard, where it just sits there for months if you don't run it dry before the season ends.
Jim DeBruycker
Not a pro, multiple Schluter Workshops (Schluterville and 2013 and 2014 at Schluter Headquarters), Mapei Training 2014, Laticrete Workshop 2014, Custom Building Products Workshop 2015, and Longtime Forum Participant.
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