My auto gas STC says the fuel must be compliant with the above specs; Where can I verify that the ethanol free fuel meets these specs? I have a local station that sells 87 ethanol free, supplied from the Knoxville Marathon refinery but can not get anyone to tell me if it meets these specs. I've tried calling the refinery but haven't gotten a call back. Does anyone know what I would need to ask for to get this information? Its not on a Bill of Lading....Thanks

I don't know if it'll do any good, but you might ask them for a Material Safety Data Sheet. That'll tell you what's in the gas.

I had a conversation with the FAA about using ISO Heet as a anti icing additive in airplanes. They didn't like it. I ordered an MSDS for ISO Heet and it turned out to be a higher concentration of isopropanol than scientific grade isopropanol that the Feds wanted me to run.

One question: Does your auto fuel STC permit running 87 octane auto gas?

MTV

Thanks for the thought. I looked at the MSDS I found online for it and didn't see any specs listed. It is the EAA STC that has a min of 87 octane. I do have 91 available at another location but its about 75 cents a gallon more. They said on the phone it met those specs. I may pick some up from them and ask for the documentation and see what they come up with

The document your looking for is known as a "COA" or certificate of analysis. Each ASTM fuel specification is made up of several individual ASTM test methods that verify the products conformity to a broader standard. Every refinery tests its output to verify conformity to the standard. Your local station has probably never been asked to provide a COA, but it should be available to them from their distributor.


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If you really want to know, ASTM would be happy to sell you a PDF of the specifications of each of these at $65 per item. www.astm.org/specifications/D4814 (D6227).

If you have some time and the attention span to deal with it, Chevron has a primer on Gasoline that has tonnes of good information (some of which you may care about).

http://www.chevronwithtechron.ca/produc ... Review.pdf

Happy reading.

Over the last 22 years, I've owned four airplanes and had mogas STC's on all of them.
I've never worried about whether the mogas I buy meets the referenced specs,
any more than I worry about the 100LL I buy meeting the appropriate specs for that.
My only concern is whether my mogas is ethanol-free or not.

Thanks for the info guys. I planned on running it either way but thought it would be nice to have the proper documentation if the airport board decides to harass me, which is very likely. Ill see if I can come up with a COA