Is YOUR aircraft fuel tank melting ?

[@lindsaylefaivre537]

Thanks John for your time in trying to educate us , Great video

[@RotacRepair]

Your welcome, the more the information is shared the better.

[@brucemcgimsie4544]

Thx John, this is another eye opener.

[@RotacRepair]

Sure is!

[@kentwilkens3435]

Great video John. I have the same tank. Looked good when I got the plane in 2022. Only ran Esso 94 or 91, which then was still ethanol free. By 2023 the ability to find the ethanol free gas was getting harder, and by the end of 2023, I do not think anyone was advertising ethanol free in Ontario, but some may differ. Our local station uses Esso 91, I tested it, and it definately has ethanol. My filler tube had an issue last fall, collapsed on itself. After several attempts to fix I finally Sealed (sealall) it to the filler hose, (which originally was just radiator hose) which was gas rated. Have not had a problem with that since. As for the tank, I do not remember discolouration when I got the bird, but now it has a mottled appearance. I will see if I can find some pics from 2022. I have not noticed a problem with discolouration in the gas, or the filter, but I pulled most of the gas out when it did not fly for a few months. As for carbon buildup, when I pulled the engine for its 150 hour, the piston tops were black, the lower rings locked in solid with carbon, and the upper rings half locked. I wrote that off to 1/ its first 40 hours it ran rich due to the carb needles put on top of the white plastic slide (before I bought it). 2/ my last 1.5 hours running were tethered trying to sort a charging issue with most of that time running at 3k rpm. Perhaps the resin in the fuel was a contributor. We tore the engine down to the crank, and notice no other issues as you described, nothing of note on the piston sides below the rings, and no resin building on the crank or anywhere else. I had ordered a tank in the fall when I had the issue with the neck, but it never did get shipped, and I didnt push it as the replacement likely meant moving the fill point and other hassles. Flying "on condition" keeping an eye on it. Also considering switching to wing tanks. Great video again.

[@RotacRepair]

Please proceed with caution, I believe from your description you have all the melting tank symptoms.

[@SuperMurrayb]

Thanks for the warning. Ethanol does dissolve many plastics but that is not the only problem with fuel that contains ethanol. Ethanol will absorb water from the air and form an ethanol-water solution. If that is exposed to the air it will absorb acetobacter which will convert the ethanol into ethanoic acid. That acid will then react with most common metals like aluminum to form salts. This causes pitting and will leave small crystals where the metal used to be. One way to prevent problems is to drain the fuel completely after every use. The other alternative is to remove the ethanol. If the fuel is agitated with water the ethanol will move into the water. IF the water is then decanted the remaining fuel will be ethanol-free. There is no simple solution to this problem as long as goverments continue to mandate ethanol in the fuel.

[@RotacRepair]

Thank you for the superb input. Yes it absolutely absorbs water. I’m always stating “after 30 days in the tank, drain and refill with fresh fuel”

[@SuperMurrayb]

@@RotacRepair You are welcome and I think your video is important for engine reliability. It would make sense to ban ethanol-blend fuels for aviation. It is not like an aviator can pull off to the side of a cloud, set the parking brake, and wait for a tow truck to come and tow the aircraft into the shop. It would make more sense to give people the option to buy ethanol-free fuel if that is what they want to use.

[@patrickmckowen2999]

Good info 👍

[@RotacRepair]

Thanks 👍

[@aerialambitions3066]

John! I love your insight and videos! How much for a tank?!!!! $$$

[@RotacRepair]

Please email me, [e-mail]

[@thomassnyder6750]

I fly a 503 and I currently buy ethynyl-free fuel. E10 85 octane is OK to burn in my Rotax engine?

[@RotacRepair]

87 A.K.I. rated gasoline is minimum for a 503.

[@timothyahiggins]

Looks like the epoxy is failing, resulting in delamination.

[@RotacRepair]

Correct, that is the warning I’m attempting to pass along. Thanks for your comment.

[@RotacRepair]

Correct, that’s the warning I’m attempting to pass along. Thanks for your comment.

[@260bossute]

How is this not an airworthiness directive for inspection??

[@RotacRepair]

I believe that would be prudent.

[@techlifetime4098]

What about the plastic 10 gallon tanks? Are they affected by the ethanol?

[@RotacRepair]

The “plastic” fuel tank are not affected by ethanol, it’s just the fiberglass tanks.

[@flexairz]

use vinyl ester resin.

[@RotacRepair]

Thanks for your suggestion, however it’s aluminum for me.

[@challenger2ultralightadventure]

What is your opinion on using 100LL in a 503 or 582?

[@RotacRepair]

100LL is far more octane than a 503-582 requires, however when I’m on a trip I have occasionally used 100LL. Its very expensive compared to car gas, it kills the spark plugs in 25 hours and dirties up the inside of the engine. On the plus side your fuel tank won’t melt.

[@VerticalSpeed1987]

So what's the solution here? Do we all buy aluminum tanks from John? What are the thoughts on alcohol resistant gas tank sealers like POR15? Coat the inside of fiberglass tanks with this??

[@RotacRepair]

@@VerticalSpeed1987 I know of one tank sealer material that won’t stick properly if the tank has ever used premixed.