"C J Campbell" wrote in message
...
Don't fill your plane before putting it away?

We turn the fuel valve off or turn it to left or right tank -- this seems
to
mitigate the problem considerably, though I am not sure why it does this.

Because in any position besides the BOTH setting, it prevents fuel from
flowing between the tanks... or more precisely, from the (slightly) upper
tank to the lower tank and out the lower tank's fuel vent.

Eric