Long time listener, first time caller.
I'm in a partnership on a M20f. Great plane and good avionics package including dual aspens. Over the last year or so, we have noted the right tank loses up to 10+ gallons if she sits without flying over say a 2 week period. No fuel staining is noted on the floor. My partner feels there may be a void within the fuel system that is slowly filling over that time while I think there’s an internal leak with evaporation. Either way, I don’t like it.
I wondered if anyone else has any experience with this type issue. It’s going into annual later this month. The last guy to look into this didn’t find anything.
Thanks