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Fuel leak with some ethanol-free

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At the advice of multiple mechanics and EZ owners, I've been running 50/50 ethanol-free 90 octane fuel and 100LL (yes, low compression pistons). In theory it should be great - Less lead to foul plugs (but still enough to lubricate), no ethanol to eat the epoxy, and save some $$!

The aircraft developed a leak in (at least) the right fuel tank. This annual I cut it open and sealed all surfaces with slow cure EZ Poxy. Going forward, should I continue running the 50/50 mix, or could it be the cause of the leak?

I've read that even though I've avoided the dreaded ethanol, there still could be a number of additives in auto fuel that may be even more damaging than ethanol. After this experience, I'll be pissed if I have to open up the fuel tank again.

Thanks for sharing your thoughts

Robert M.

Long EZ 329W  |  O-235 updraft

Pilot / engineer / amateur mechanic

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Just my opinion but ethanol free Mogas  still can have 150 nasty chemicals

A 50/50 mixture with 100LL might take twice as long to eat up your tanks.   Feel better now?  🙂
I don’t see much problem with lead— I use auto plugs and run very lean 

Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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