Rob and JimR,
Jim answered as what is required for old M20s. My C rusted, and rough oxidated surfaces always leaked a drop or two after rain.
One day it was a full cup and then some. A hole opened where the sheet metal was bent/shaped in the neck.
My plane was doomed to the sales yard at that moment.....
Really it doesn't take much to fix that problem, JimR outlined getting the new part insalled, but I preferred more HP, newer systems, modern avionics, leg space in the back, fuel injection, near real IFR capabilities, newer paint... And less money in my bank account.
It turns out my old necks and caps were no longer OEM. News to me, no record of it either. Plastic caps on a mooney....not OEM, possibly race care mod.
I may have been angry that day. I bought new OEM caps and gave them to the new owner as a reminder of the work he needed to complete. He got a set of seat belts too...
Rember, if you don't see a meniscus...spit in the cup, you should now.
With good seals you should find ice on cold days in NJ. No ice, water must have gone somewhere....if you find ice, a bag of hot water is the next best way to get the caps open.
I ask the fuel person to leave my caps off. I am not shy about this situation. It helps me to remember what I need to do... How full they are, and sump, while I'm there.
The ovation's tanks are always dry, SS fuel necks and good seals are the main reason. No rust, no holes, no water....
Best regards,
-a-