Posted for "Bob B." <rbelshe@comcast.net>:

 Randy,
 Did you install a separate valve, or did you find a 3-way valve?    How did
 you tie the return line into the tank?
For reasons that I cannot understand, I have never seen this problem in 10
 years of flight.
 Bob Belshe
 Moraga, CA
 Lancair 235/320
 <http://home.comcast.net/~rbelshe/>