My Perkins seems to have something similar. The returns from the injectors
go back to the fuel filter. Then another line from the fuel filter goes back
to the
tank. Not sure what is happening but it does seem that the returned fuel is
being
mixed with fresh fuel. The Perkins actually returns very little fuel
according to
the Entec folks. When I was having some initial problems with my genset, the
Entec folks said the Farymann engine is a "full flow return" system and it
returns
alot of fuel (gallons per hour). He said that the genset makes a pretty good
fuel polishing system but filters will clog much quicker than I was used to
if
I have dirty fuel. He said that the Perkins may only return a few
tablespoons of fuel
per hour. Last fall I tried to empty one of my tanks by drawing fuel from
one and returning
it to the other. After an hour of running the engine, there was no
detectable difference
in fuel level in the tanks.

Doug
s/v Calista

"Glenn Ashmore" wrote in message
news:mbNae.33637$Zr.18735@lakeread08...
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?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com