Alcohol-free fuel: how to find it, how to test it

Jerry Quint of California, part owner of an aircraft with a Jabiru engine, wonders how to go about finding auto fuel that does not contain alcohol. He also wonders how to be sure that the fuel is alcohol free.


Jerry Quint of California, part owner of an aircraft with a Jabiru engine, wonders how to go about finding auto fuel that does not contain alcohol. He also wonders how to be sure that the fuel is alcohol free.

I have addressed this question before, but I thought I would try to shed a little more light on the subject.

As an answer to the energy crisis, ethanol is a very good farm subsidy program. One starts to wonder about our “”leaders”” when the answer for solving the energy crisis is to pay people to produce a fuel that takes more energy to produce than you get out of it. I must assume that it has to do with new math and that old engineers are not supposed to understand or even question the system. But I digress.

On the positive side, ethanol does reduce the level of carbon monoxide and unburned hydrocarbons in the emissions of most automobile engines. It does this by leaning out the air/fuel mixture coming out of the carburetor going into the engine. This leaning out does not have a great affect on the operation of most water-cooled auto engines.

However, in an air-cooled aircraft (or even an air-cooled motorcycle or lawnmower engine) the leaning out of the air/fuel mixture will move the temperatures and pressures in the cylinder closer to peak, which can cause burnt valves and the loss of other useful engine components. There also is the factor of the ethanol-containing fuel attacking the plasticizer agents in the rubber components of your aircraft.

Although ethanol may not cause an instantaneous crash-and-burn of your engine, it will probably have some negative long-term effects.

How do you ensure that you are not getting an ethanol containing fuel? Usually there is a small sign on the pump informing you when the fuel contains ethanol. But these signs are not always accurate. During certain times of the year and in certain locations, all fuel may contain some ethanol. Second, many areas outside the required areas may receive ethanol-containing fuels simply because that is the only fuel available. And, third, your local fuel dealers may not know that the fuel delivered to them contains ethanol.

The best procedure is to find a dealer near you who thinks its fuel does not contain ethanol. Then test each batch before using it. The test is to put a measured amount of water in the bottom of a flask, then add fuel and shake it up. If the amount of water is less or more than when you started, it probably contains ethanol. Accuracy is important, so make your measurements carefully.

Lastly, remember that alcohols are not inherently bad ? they just don’t belong in an airplane or a pilot.

Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil. He has been a private pilot since 1985. You can contact him at Visser@GeneralAviationNews.com.

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