Charlies'
suggestion of the Facet transfer pump is what I've been using. I use a
'T' in the fuel return line to the main tank for the transfer pump so it didn't
even require an additional fitting in the tank (above what is necessary for
EFI). The Facet has a check valve function internally.
There really is not a simpler system that I am
aware of.
Well; there is, but of course it is
dependant on air frame design. My Velocity has gravity feed from both mains to a 3 gallon sump,
gravity feed from sump to the EFI pump; regulator return to the sump. Now
that’s simple.
Al G