Glenn,

I have never seen this on a boat and I might be a tad leary. The fuel
retuen usually stitches along the injectors and then gets the top of the
injection pump and then head back tot he tank.

In the engine test labs that I have run over three plus decades, we have
seen non-condensable gasses (little bubbles) coming back to the the
float controlled level tank typically used in such facilities. I will
not go into what problems that might cause if not removed.

By the By,
Two flow instruments and approriate totalizing equipment is unreliable
largely becuase of the temperature differential of the two streams. It
can be done (we did do it - once), but it requires really expensive mass
flow sensing transducers.

Matt Colie

Glenn Ashmore wrote:

Yesterday my neighbor had to show off his new diesel pickup. It has one of
those trip computers that displays MPG and range so I was interested in
seeing how the fuel flow sensors were set up. By tracing the supply line
from the injector pump it was easy to find the supply side sensor but the
return line, instead of going back to the tank went through a finned cooler,
then into a heat exchanger cooled by the new fuel and back into the supply
line after the flow sensor. That eliminated the need for a second sensor on
the return line which simplifies the net flow calculations, maintains the
fresh and recycled fuel at the same temperature so the density is constant
which further improves the accuracy of the flow measurement and reduced the
load on the filter.

Anyone seen this setup on a boat?