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Ethanol in gasoline

  • Tapio Pirilä
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3 months 23 hours ago #17253 by Tapio Pirilä
Tapio Pirilä created the topic: Ethanol in gasoline
As a new 912UL owner I am wondering whether to use 95E10 with 10% ethanol or 98E5 with 5 % ethanol now in autumn when condension water may occur in tanks. I assume that the possible condension water is dissolved in the ethanol. However, as I have found in literature, the diluted ethanol may not be dissolved in the gasoline and two different solutions, gasoline and diluted ethanol may be separated and cause problems. So I conclude that the higher ethanol % in 95E10 dissolves more water than 98E5 and the risk for separation is smaller? Agree?

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  • Bill Hertzel
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2 months 4 weeks ago #17271 by Bill Hertzel
Bill Hertzel replied the topic: Ethanol in gasoline
You are correct!
E-10 fuel will absorb twice the amount of water that E-5 will.
If you have water in your tank, it most likely entered the tank as liquid water and not as water vapor that later condensed.
The conditions to cause any water to condense internally in a fuel tank are very difficult to create in real life.

E10 fuel will absorb up to ~0.5% its volume of water.
That means that 20 gallons of fuel will absorb >12 ounces of water.
That is a cup and a half!

If you consider that 50:1 2 cycle fuel contains 2% of a non-burnable Oil...
<0.5% (200:1) of non-burnable water in the fuel will have less than 1/4 the effect that the oil does on performance.

If you ever were to get fuel so bad that it phase separated,
diluting the bad fuel with fresh fuel will reverse the separation and re-absorb the water.

If you use E-0 fuel, remember that it will not absorb any water.
The small amount of water found in tank sumps become a thing of the past when E-10 fuel is used.
The following user(s) said Thank You: Ken Ryan, Tapio Pirilä

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  • Roger Lee
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2 months 4 weeks ago - 2 months 4 weeks ago #17274 by Roger Lee
Roger Lee replied the topic: Ethanol in gasoline
Hi Bill,

FINALLY a voice of reason. :) My background is Hazardous Materials on the fire dept. (retired)
I try to explain about ethanol myths, but sometimes it just falls on deaf ears.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell
Last Edit: 2 months 4 weeks ago by Roger Lee.

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