Ethanol Free Fuel Issue

[Piper J3]

Not only the pump and hose, but also the fuel selector valving and inline filter need purging. I'm guessing maybe 1/2 gallon of previous dispense before you start getting the real stuff...

[JPalese]

Originally Posted by N427EF

If I read that post correctly the op used 100LL or ethanol free mogas on that engine.
It is precisely why that kind of corrosion formed because the water in 100LL and ethanol free mogas separates out and settles in low spots in the fuel system. As someone pointed out in that thread, ethanol mogas keeps the water in suspension and it passes harmlessly through the combustion cycle.

Partially Correct.

At some point, if there is enough water in the fuel, the ethanol can not absorb any more water and the ethanol comes out of suspension (the weight of the absorbed water?). If memory serves me correctly when this occurs it makes the fuel look cloudy.

As to the corrosion: If E0 - is corrosion caused by water that can be sumped out of the low points in the fuel system and is so removed;

or

if E10 (or greater), is the corrosion caused by the constant presence of water that can not be sumped or removed. Water is still water, even if held in suspension, and the water is in constant contact with parts not expecting a visit.

[funflying]

I had my first experience with water and sediment in some 91 octane ethanol free gas I get in some tanks I take to this station in the Denver area. When I sumped the tank at the gascolator I got this cloudy and reddish sample. Ick! I sumped again and more cloudy gas and it kept coming.

A friend of mine was there who worked at the FBO and he said it looked like water. He let me bring the sample to the FBO and did a hydro test, and it was at the top of the scale for water. I wish I could post the photos off my phone that I sent the fuel distributer.

All the fuel was removed, couple of gallons to flush the lines, and a gascolator clean up. Quite a bit of sand looking debris on the screen. Carb bowls looked okay. I will test with some 100LL from the FBO and go to a different source for my ethanol free gas.