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Ethanol Free Fuel Issue

WingedFrog

Well Known Member
I have been usng Ethanol free gas for two years as I have a service station close to my airport that carries it. Today on my refueling trip I noticed that the price per gallon had dropped almost $1 since last month, nothing close to the drop of regular gasoline. Looking at the pump more carefully I also noticed that the octane displayed for non ethanol was now 89 vs 92 last month. Indeed the appellation of this type of gas is now Plus vs Premium before. I discussed these changes with the owner who told me that their supplier is now receiving Ethanol free gas that is 90.1 octane and has he did not have stickers with this grade to put on his pump he applied the 89 one.
Now the question is: will my Rotax 912 ULS run on 90 octane gasoline?
After a search I found the following thread on the subject:
http://www.vansairforce.com/community/showthread.php?t=87540
I am reintroducing this subject because I suspect that what has happened in my area might also have happened elsewhere. If you are using ethanol free gas watch out next time you refuel your RV-12.
 
I think it depends on the supplier. I live in an area of Western Kentucky, near Kentucky Lake, were many station offer what they call boat gas. It is 89 octane ethanol free fuel, which is actually a blend of regular, and premium. I also have a local supplier who sells ethanol free 91 octane. I can get ethanol free 93 octane premium, but I have to drive 60 miles to get it. I do, and carry a 55 gal drum with me. According to that supplier, all of the fuel in our area comes from the same pipeline, located in Nashville TN. He says that only two grades are available, 87 octane regular, and 93 octane premium. He says that anything else is a blend, and that the ethanol is added after the pipe line distribution, not through it. The suppliers blend fuel strictly to lower their cost so that they can offer more competitive pricing. So far, I have been able to get 93 octane premium, but it is at a slightly higher price. For what this is all worth............Tom
 
This is why I gave up on using ethanol free fuel. I just use 93 E10 and fly merrily on. It's more important to have the octane than it is to eliminate the alcohol.
 
Amen

Randy has it exactly right.
I cannot understand this crazy obsession with not wanting to use
E10.
As far as I know 93E10 is available everywhere and Rotax engines are approved for running on E10.
 
Randy has it exactly right.
I cannot understand this crazy obsession with not wanting to use
E10.
As far as I know 93E10 is available everywhere and Rotax engines are approved for running on E10.

Probably because of the shorter "shelf life" of fuels that contain ethanol. I imagine there are other technical reasons too but they've been hashed out on other threads as well.
 
Good to hear

The success of E10 fuels is good to hear about because getting the ethanol free, 91 octane, is a bit of a drive for me. In the good flying season I use it regularly and fly more frequent. Winter rolls in and I switch to 100LL because of the stability as the plane sits more.

I may start using the 93 E10 this summer and see how it goes.
 
Also, gasoline without alcohol has more BTU content. E10 has 96.7% of the energy of straight gasoline. Doubt if you'd notice... :D
 
This is why I gave up on using ethanol free fuel. I just use 93 E10 and fly merrily on. It's more important to have the octane than it is to eliminate the alcohol.

I am not an expert on fuels, but I started out burning 93 E10 in my LS1 conversion. After 20 hours, I noticed a lot of build up in the filters. I bagged it and took it to a guy who sells 90 E0. He pointed out that it was the same stuff he found when he did a phase separation test. He showed me the test jar, and the same junk that I found was at his phase separation level. Turns out that the yellowish fibers are Corn Silks. The little brown globs are Corn Syrup. I switched over to 90 E0, and also use some 100LL on cross countries. Filters have been clean since then.

John
 
Take a look at the pictures of the fuel pump that was disassembled recently, and posted on this forum, which shows all of that interior corrosion in just 20 hours of operation, which might be another good reason to keep the ethanol out of your gas, in you can.
 
In the nice and wet Pacific Northwest, what fuel do you suppose Mr. Van himself, uses in his Rotax? Yep, 93 E10 (I'm told). I fly at least once a week and my -12 sits in a dry hangar. Having the fuel absorb water is a non-issue for me.

BTW, there are thousands of Rotax engines in Europe using 30 percent ethanol based fuels with few issues. I'm not too worried about it but you should use the fuel you feel most comfortable with. If it takes you out of your comfort zone, then don't let anyone tell you what YOU should do.
 
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Having used E10 almost exclusively in every car, pickup, motorcycle, scooter, mower, snow blower, edger, leaf blower and weed whacker we've owned in the past three decades or so, and having had exactly zero problems related to corrosion, water absorption and hose deterioration... I guess I'm OK with using it in the Rotax if Rotax and Van's are OK with it.
 
Take a look at the pictures of the fuel pump that was disassembled recently, and posted on this forum, which shows all of that interior corrosion in just 20 hours of operation, which might be another good reason to keep the ethanol out of your gas, in you can.

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.
 
Initially (the first 6 month I flew my -12) I used E10 premium, without any problem. Then comes winter and the plane was left about 2 months with a full tank of E10 gasoline. My local Rotax guy told me that, depending on weather conditions, E10 gas may start degrading after 1 month of storage. I did not want to take the risk and dumped the content of the tank which was a bit cumbersome... and promised myself not to use Ethanol fuel any longer. As the service station is close to my A/P it worked well until... go back to the first post of this thread.
Still mulling what to do based on the interesting feed back provided above. At this point I am reluctant trusting any Ethanol free source for aviation usage. My preference would be to go back to E10 premium, except for January and February when I would fill the tank with 100LL. I figure it would result in 100LL usage low enough (including refills on trip stops during the rest of the year) to make minimum lead deposit inside the engine.
Only time will tell if this is effective and workable.
 
There may be another option to consider. I am certainly no expert, but from what I have read what you're concerned about is not only water absorption from the atmosphere but also octane loss from evaporation. The water problem can be minimized by keeping the tank full and the cap on. Less surface area exposed to air, and less air exchange with the humid outside world, means less water absorbed.

Everything I have read indicates that if you keep the tank FULL, you have less to worry about. There's less surface area to either absorb water from the atmosphere, or evaporate the lighter hydrocarbons. On the other hand, if you have a gallon or two of room in the tank, topping it with 100LL would probably provide a pretty good little boost for fuel that's been sitting for a few weeks.
 
I just go down the street and buy what ever comes out of the premium pump. In 420 hours and 4 years I haven't fallen out of the sky yet!😀
 
I am not an expert on fuels, but I started out burning 93 E10 in my LS1 conversion. After 20 hours, I noticed a lot of build up in the filters. I bagged it and took it to a guy who sells 90 E0. He pointed out that it was the same stuff he found when he did a phase separation test. He showed me the test jar, and the same junk that I found was at his phase separation level. Turns out that the yellowish fibers are Corn Silks. The little brown globs are Corn Syrup. I switched over to 90 E0, and also use some 100LL on cross countries. Filters have been clean since then.

John

This is interesting - I found some gunk in my filters after using 92 E0 and 100LL. My brother-in-law runs the mass spec at major university chem department. We tested it and, yup, you guessed it, ground up dinosaur bones........ :D
 
This is interesting - I found some gunk in my filters after using 92 E0 and 100LL. My brother-in-law runs the mass spec at major university chem department. We tested it and, yup, you guessed it, ground up dinosaur bones........ :D

Somebody had to say it. :D
 
What filters are you guys referring to? The gascolator or an inline filter you use during fueling?

I have a 40 micron reusable filter inline between the wing tank and the fuel system, on each wing. I have another filter just before the engine at 10 microns, but it's a throw away. The inline filter was put there to catch loose proseal, but it will catch anything else that's there. My engine is an auto conversion, so there are differences in fuel delivery.

John
 
A little update: I found a Sunoco service station serving 93 octane ethanol free premium a month ago but... on my last trip it had gone down to 91! The owner says he will know in April if it goes back to 93 (that would be for summer). In the mean time he sells an "octane booster" additive that claims to bring the octane of a 17 Gal. load to 100 octane. I checked the container but there were no indication of the composition of the content. I doubt Rotax would agree to support such mixture under warranty.
Back to ethanol fuel for the time beeing.
 
A little update: I found a Sunoco service station serving 93 octane ethanol free premium a month ago but... on my last trip it had gone down to 91! The owner says he will know in April if it goes back to 93 (that would be for summer). In the mean time he sells an "octane booster" additive that claims to bring the octane of a 17 Gal. load to 100 octane. I checked the container but there were no indication of the composition of the content. I doubt Rotax would agree to support such mixture under warranty.
Back to ethanol fuel for the time beeing.

91 octane should be OK, shouldn't it?
 
From my copy of the POH:

Actually, everyone flying a Rotax should be referencing the Rotax Service Instructions for use of the proper fluids in and on your engine. They change sometimes. The proper service instruction is SI-912-016R8 (as of today). Here's the link.

Lots of good stuff here. Its "must read" material for properly maintaining your Rotax.
 
A little update: I found a Sunoco service station serving 93 octane ethanol free premium a month ago but... on my last trip it had gone down to 91! The owner says he will know in April if it goes back to 93 (that would be for summer). In the mean time he sells an "octane booster" additive that claims to bring the octane of a 17 Gal. load to 100 octane. I checked the container but there were no indication of the composition of the content. I doubt Rotax would agree to support such mixture under warranty.
Back to ethanol fuel for the time beeing.
I may have inadvertently gotten us sidetracked. My original response was more aimed at why the 91 octane ethanol free wasn't good enough and necessitated "Back to ethanol fuel".
 
Randy has it exactly right.
I cannot understand this crazy obsession with not wanting to use
E10.....

If you saw the aluminum float bowl of one of my generators after sitting idle for just a few months, you would NEVER put that trash in your plane!
 
Actually, everyone flying a Rotax should be referencing the Rotax Service Instructions for use of the proper fluids in and on your engine. They change sometimes. The proper service instruction is SI-912-016R8 (as of today). Here's the link.

Lots of good stuff here. Its "must read" material for properly maintaining your Rotax.

And by golly, it says the same thing. 91 AKI.
 
Thank you all for the clarification on the 91 AKI requirement. I was under the wrong assumption that 91 was the intermediate fuel grade sold in most service stations that I remembered as inadequate for the Rotax. As a matter of fact the intermediate grade is 89 not 91. My mistake!
 
I guess the next obvious question is how trustworthy the octane rating on the pump is. I don't have any way to test the actual octane that I know of. If 91 is our minimum and the pump is labelled "91 octane", can we trust it?
 
I guess the next obvious question is how trustworthy the octane rating on the pump is. I don't have any way to test the actual octane that I know of. If 91 is our minimum and the pump is labelled "91 octane", can we trust it?

Good point! Only hope is that a major brand has a reputation to live up to but I would be concerned buying from a no brand station.
 
Good point! Only hope is that a major brand has a reputation to live up to but I would be concerned buying from a no brand station.

In our area there is reason to believe all non-contaminated gasoline is coming from the same distributor regardless of the sign on top of the station....
 
Good point! Only hope is that a major brand has a reputation to live up to but I would be concerned buying from a no brand station.

In our area there is reason to believe all non-contaminated gasoline is coming from the same distributor regardless of the sign on top of the station....

Our local stations (regardless of "brand") that had 93 non-ethanol switched to 90 at the same time a few months ago.
 
In our area there is reason to believe all non-contaminated gasoline is coming from the same distributor regardless of the sign on top of the station....

Our local stations (regardless of "brand") that had 93 non-ethanol switched to 90 at the same time a few months ago.

It's probably the distributor. Here in the Atlanta area, there is only one distributor of ethanol free gas - Green Oil Company. All of it is the same, 90 octane, only the price varies from station to station.

John
 
A fuel distributor told me that removal of the 10% ethanol from 93 AKI premium motor gasoline reduces the rating to 90 AKI. Many marinas offer that variation as some older boat engines can not tolerate ethanol.
 
one comment

I know from past experience that if you fill up the first small amount is what the person ahead of you used..ie; 87 octane..that is what was in hose and pump ...so when I filled up scooter which took very small amount..2 gallons a good portion was what ever the person ahead of me used..don't know if it is relavent...just food for thought...
 
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...
 
Ethanol

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.
 
Water and stuff

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.
 
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