Removing water from E10 fuel..

[IRGuy]

I ran across this short article about removing water from E10 fuel.. It might be old news to some of you, but it may help others, so I am posting it here...

http://www.heartlandboating.com/July-20 ... -E10-Fuel/" onclick="window.open(this.href);return false;

[Peter]

Don't be so sure this article gets it right.

The water doesn’t drop to the bottom of the tank like it used to in the pre E-10 days. Instead it mixers with the ethanol and is distributed throughout your tank of gas. Then the water-ethanol mix passes through your fuel system to your engine and “burns harmlessly.” Well I don’t know how harmlessly, but that is what they tell you.

There is never any water in the bottom of the tank until phase separation takes place.

WHEN phase separation takes place ALL the water and ALL the ethanol drop out TOGETHER and form a puddle in the bottom of the tank. This occurs when the water content exceeds a critical value,(0.5% for E-10) an then wham-O… phase separation.

Summarizing: there is no water in the bottom of the tank at all until there is phase separation.

But once phase separation has occurred you can’t just drain off the bottom and use the rest of the gas because now that which remains has been deprived of ALL its ethanol along with the water. So now it is out of spec to the low octane side. This can cause pre-ignition (knock) which is brutal on engines. Knock most commonly occurs when an engine is under heavy load. For instance in a car when accelerating quickly or driving up a steep hill; or in a boat basically all the time.

The old fashioned water separating fuel filters won’t work with E-10. They relied on a settling bowl where you could see a puddle of water gathering at the bottom of the bowl and drain it off. But that doesn’t work with E-10.

Do not kid yourself that by putting in some super-small micron fuel filter you are somehow magically separating out the water and capturing it in the filter element. You are not. The water and the ethanol are together as one in the fuel. And as much as we hate it, you need the ethanol to get to the motor to avoid knock. But the water shouldn’t matter anyway because “the water and ethanol mix burns harmlessly in your engine.”

However, if you DO get a puddle in the bottom of the fuel tank then you have phase separation, which is another issue altogether. You can proceed one of three ways.

One is to draw off the water/ethanol bottom and dispose of it somehow, and put new ethanol in the remaining fuel to bring it back up to spec.

Next is to add more ethanol which will cause the ethanol-water puddle to go back intot he gasoline, but now you have someting like E-12 or E-14 or whatever.

The other way to go is if you have a mostly empty tank top it up with fresh E-10. The addition of a lot of fresh E-10 will raise the amount of ethanol in the whole batch to the point where the separated phase will re-mix with the gasoline. Of couse this option is n't open to you if your tank started out full.

The last issue is that ethanol evaporates quickly. Most cars do not have straight open-to-the-air fuel tank vents. Boats do. Over time the ethanol will evaporate away from your boat fuel tank and leave you with low octane fuel. This is mostly a problem after a winter of storage. Many yards prefer to store boats with their tanks full. This is no longer good practice for the health of your engine because come springtime the first tank of gas will be out of spec; low octane. Better to store the boat with tanks mostly empty. Then when you commission, top off the tank with fresh E-10. Any remaining fuel in the tank will be brought back into, or close to spec by the fresh load of ethanol in the new batch of fuel.