Diesel Fuel Returns

[surfdancer45]

I have just about completed a changeover on my diesel fuel system, multi filtration, new fuel manifolds and all new Parker lines. I have two questions, Did the early 70 Hatts return diesel through the rear fuel tank plates and did the connections have rods extending the fuel return down into the fuel tanks? My boat was orginally gas so I do not have the diesel diagram in my manual. Thanks Bob

 

[34Hatt]

Not sure if they had a tube going down should not be a reason for that. The returns go into the front plate should be in the front on the outboard side. You do not want it in the rear where your pickups are because of cause air and turbulence.

 

[REBrueckner]

I can think of no reason for a return tube way down in the tank.

Calder shows a return line inserted just a little (maybe a few inches) into the top of a fuel tank. (Page 273, second edition Boatowners Mechanical and Electrical Manual) It is adjacent to the pick up line and looks to be mounted in the same tank plate. The pick up line extends to a low point in the "ideal" tank. A vent line also appears to originate from the same plate, none of which seems a necessary placement.

 

[surfdancer45]

There has been some instances of fuel draining back through the returns on Cummins diesel (see threads at boatdiesel.com). The ball valve in Racors are for water and do not stop fuel drain back so they do not solve the problem. My understanding is that having fuel returns extend down into the tank solves the problem. So far I have been using shut offs on returns to prevent having to bleed air out of my engines. Thanks for your responses. Bob

 

[REBrueckner]

Cummins uses a different fuel pump/injector system than Detroits...I wonder if the Detroits are susceptible as well..have never heard so..