Brown Goo Plugging Fuel Drain

[JPerkins]

Anybody run into this stuff plugging the fuel drains on the wing tanks? Don't find anywhere else in the tanks or other fuel drains or gascolator and pickup screens. Just on the tank drains.
Had the left tank drain plug up 10 flight hours/4 months ago. Just pulled this from the right tank drain.
I blend my fuel 30% AVGAS to 70% mogas. No ethanol in the gas here but I'm getting suspicious of something else maybe.

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[JPerkins]

Header is supposed to read GOO. Thank you autocorrect.

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[Steve Pierce]

Header is supposed to read GOO. Thank you autocorrect.

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I fixed the auto correct but no idea what the brown goo is.

[JPerkins]

Thanks Steve.
Haven't shown the sample to my IA yet, but he was guessing slosh seal. However like I said when I look in the tank the thing is spotless inside.

[Jeff J]

While alcohol isn’t the only thing added to mogas, I doubt the goo came from that. Since your tank is clean the goo could have been pumped in with the gas. “Goo” makes me think sealant more than seal.

[SMO22]

Did you use EZ Turn fuel lube lately? I used too much on a fuel sender gasket and it came out in brown clumps out the drain, nothing that size though and didn't plug it up.

[SMO22]

How are you testing mogas? The only sure way to test is the water mixed with gas and shake it and see if it mixed.

For those interested, here is the tester I use, https://www.eaa.org/en/eaa-shop/2265...cohol-test-kit

Bottom pic is what will happen with some E 0% fuel you find, it won't be free after you test it, the water will mix with the Ethanol and the amount of gas is less, indicated by the water above the original water line, this pic is showing about 4 or 5 % Ethanol

If you shake it and it is still at the original water level of 0, than it's E 0%

[Gilbert Pierce]

Put a drop of red food color in the sample. Food color is alcohol soluble but won’t mix with gasoline.
If the sample immediately turns pink it has alcohol in it. If the drop of food color sinks to the bottom and just rolls around you have real gasoline. Much quicker test than the water method; no shake and wait for the sample to settle out.

[SMO22]

Put a drop of red food color in the sample. Food color is alcohol soluble but won’t mix with gasoline.
If the sample immediately turns pink it has alcohol in it. If the drop of food color sinks to the bottom and just rolls around you have real gasoline. Much quicker test than the water method; no shake and wait for the sample to settle out.

What brand food color works? I tried a couple different brands from local food stores, neither gave reults I trusted. I never got the food color drops to disolve in known ethanol gas, had 100LL and pump gas that tested positive for ethanol with my tube water test, dropped food color into both samples and the food color did not disolve in the 5 % ethanol gas it broke into a few smaller drops in the jar never diluted with the ethanol gas. The avgas did the same but didnt break into as many small drops. If I found food color that diluted with ethanol gas instead of just turning into drops in the bottom of the tube, I would trust that.

[JPerkins]

Update: Brown goo has dried to little brown boogers. Still uncertain what it could be. It's now hard and brittle.
I will try the water test. The bulk plant had stated to me in the past that they do not carry any gas with ethanol as the majority of their fuel sales is to the fishing fleet. And ethanol in a boat would wreak havoc on that damp environment.

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