"RW Salnick" wrote

On Eolian, a developing filter blockage doesn't manifest itself until the
lift pump cannot deliver sufficient fuel to the injection pump. At that
point, the injection pump begins to suck air from the return line,

Good point for the general populous. I forgot that I was predicting the
behavior of my system with the Yamaha peculiarity (at least on the QM
series) of there being no return line to the tank. Return fuel is pumped
back around to ahead of the injector pump so there is no way to suck air
back into the system unless there is a leak in the piping.

--
Roger Long