Gas cap leakage 750 STOL. I fill to 2" below the opening, but still, get leakage on the grass even with new gas cap gaskets. Solutions?


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Comment by John Burns on November 20, 2022 at 6:25pm

Same fuel cap.  Just wondering of the return fuel is pressurizing your tank some way and causing the leak.  Just something to check on.  I don't know your exact fuel system setup.  Robert Helms with UL power might also have some thoughts if you reach out to the them to see if the fuel system is installed the way they recommend. 

Comment by Michael A Housewert on November 20, 2022 at 5:58pm
John ...Interesting. So what you are saying is that your plane does NOT have fuel return as it is carborated? Do you have a different style fuel cap?
Comment by John Burns on November 20, 2022 at 5:14pm

I have not had any problem with my 750 STOL with just over 100 hours on the tach and I fill the tanks completely full.  I have a carbureted engine and yours is fuel injected.  I wonder if this problem has something to do with your fuel return to the tanks?

Comment by Jimmy Young on November 18, 2022 at 6:00pm

The quick and easy fix:

It is from the thread John Austin referenced above. Fill the copper vent with some salt to bend it without crimping. I’m using these, bought them from John as I recall. 

Comment by John Austin on November 17, 2022 at 1:32pm

Try this:  Modified "Snorkel" Vent Cap

Works for me!

Comment by Michael A Housewert on November 17, 2022 at 1:17pm

The fuel "stains" are on the top of both wings starting at the fuel cap and running down to the flaps.  While taxing, the fuel is completely visible dripping from the trailing edge of the flaps, onto the rear side windows, and the smell of fuel is very evident. 

Comment by Bob Simmons on November 17, 2022 at 12:16pm

Are you sure it's coming from the caps? Fuel sender leakage isn't all that uncommon.

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