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Fuel routing problem

Discussion in 'Post Yacht' started by Eric G, Jun 22, 2015.

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  1. Eric G, Jun 22, 2015
    #1
    Eric G

    Eric G New Member

    Joined:
    Jun 22, 2015
    Messages:
    1
    Location:
    Palm beach, Florida
    I recently purchased an 1987 46 post. The previous owner rebuilt the engines buts never finished the project. I have been re dressing the motors and ran into a issue with the fuel lines. The boat has 671 detriots Johnson and towers. I have the pickups from the rear tank to both motors but don't see we're the return lines are. the fuel comes out of the tank into the strainer, from the strainer to the fuel pump, fuel pump to the primary filter, primary filter to the injectors, injectors to the fuel cooler, that's were I run out of hoses, my local shop say it should run back to the strainer on the motor to make the loop again, does anyone have the same set up and can share info or pictures? Can't wait to get her in the water just don't want any unexpected problems.
  2. Capt Ralph, Jun 23, 2015
    #2
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    12,736
    Location:
    Satsuma, FL
    After the fuel cooler, the return fuel must go back to the tank. If you re-inject it, any air will never get out.
    That gear driven fuel pump moves a lot of fuel thru the engine. Ensure proper size hoses and non restricting fittings.
    Do you only have one fuel tank?
  3. mwwhit1, Jun 23, 2015
    #3
    mwwhit1

    mwwhit1 Senior Member

    Joined:
    Jan 19, 2006
    Messages:
    239
    Location:
    Jersey City NJ\Boca Raton FL
    Mine is a few years older, but should be the same.
    Rear tank pickup #1 at the stern goes to the starboard primary filter (racor\dahl). My generator also feeds after this filter so both the engine and gen use this tank\primary filter. Your remaining setup is good, pump\secondary filter, injectors, cooler. The fuel return from the cooler goes to the rear tank return towards the front of the tank on top. Generator fuel return goes to the rear tank towards the front top. Rear tank pickup #2 at the stern goes to a fuel transfer pump that goes to the front tank pickup #2.

    Front tank pickup #1 at rear of tank goes to the port primary filter (racor\dahl). Same path on the motor. Port fuel cooler return goes to the front tank towards the front.

    Each engine should run off of each tank. Not both from the rear. The fuel transfer pump moves fuel both ways between them if needed and needs to use pickup lines. I assume your rear tank is bigger and that is why the gen runs off of that one too.

    Hard to take pics to show all of this. But maybe draw it out logically for yourself? Basically each tank has a loop from the rear pickup through the engine and back to the front return port.
  4. RT46, Jun 23, 2015
    #4
    RT46

    RT46 Senior Member

    Joined:
    Feb 22, 2011
    Messages:
    1,058
    Location:
    Long Island, NY
    my Post has the Stbd engine feed and Stbd return to the rear tank
    and the port motor feed and return to the fwd tank

    I cannot run both engines off one tank.
    but there is a transfer pump between the tanks

    the return must go to the tank, in part because the fuel is heated as it passes through the rack.

    follow the fuel line from the fuel cooler. Also the pick up and return line are in different locations on my tanks.