Finn,

Awhile back some of the Lancair guys were experiencing similar issues.  The problem was ultimately traced back to the fuel selector valve.  In these instances it was found that with the fuel pumps downstream of the selector that air was being sucked past its internal seals and showing up in the fuel line.  When the pumps were moved to a position between the tanks and the fuel selector, causing the fuel to be pushed through the it rather than sucked through it, the problem went away.  FWIW.

  <Marv>



Posted for Finn Lassen <finn.lassen@verizon.net>:

 I'm near wit's end trying to find out why I get bubbles in the line from my
facet pump to my carburators.