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Fuel system on a Post 56

Discussion in 'Post Yacht' started by Dennis serras, Jan 22, 2015.

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  1. Dennis serras

    Dennis serras New Member

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    just bought a Post 56. Can't figure out how fuel system works. Do motors draw off separate tanks or do you have to transfer fuel from aft tank to forward? Fuel gauge doesn't go down on aft tank, but does on forward.
  2. NYCAP123

    NYCAP123 Senior Member

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    Real simple. Just look at your tanks. or near your racors. There should be a transfer tube or pipe with a valve if you can change which tank you draw off. If the tanks are connected, but there's no valve, then they draw off both (but you'd have no need for a 2nd fuel gauge). If no conection they each draw off their own tank (which is a situation I'd correct). If the aft gauge doesn't go down it could a problem with the gauge, but my first guess would be that there is a transfer and the previous owner only ran off the one tank because he found the boat road better when he lightened the forward tank first.

    With fore & aft tanks they are often not accessable (such as on the Hatt I run), it probably has the valves at the Racors. In any case the valve won't be hidden or inaccessable.
    Last edited: Jan 22, 2015
  3. Beau

    Beau Senior Member

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    m
    On my 50 I have a set of valves that I can make the choice. There is a diagram in my owner's manual that explains the settings. The valves open or close the supply and return for the forward tank. Do you have that manual for the 56? Sounds like your valves isolate the rear tank. adjust them to the open setting and see if the rear tank goes down? When I shut mine, the forward tank gauge doesn't move either.
    Last edited: Jan 22, 2015
  4. Dennis serras

    Dennis serras New Member

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    Thanks guys,
    Racer valves open. One on each motor. I'll pull out manuals. What I think I'll do is top tanks off when I get back to Naples and see how much each take
    Dennis
  5. Beau

    Beau Senior Member

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    Dennis

    There may be another set of valves between your racors and tanks which allows you to adjust which tanks your engines draw fuel from. If I am interpreting your post correctly those valves at the engine are just shut off valves?
  6. NYCAP123

    NYCAP123 Senior Member

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    That's the fuel shut off. The valves you're looking for are not on the motors. Be careful when you top off that aft thank. I have a feeling it's full.
  7. Beau

    Beau Senior Member

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    My adjustment valves are located on the bulkhead as I come into the engine room. Two valves, side by side, with a cluster of blue fuel lines coming into them.
  8. Dennis serras

    Dennis serras New Member

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    I'll take pics in morning. Not sure how to get them on line, but I'll figure it out
    Dennis
  9. NYCAP123

    NYCAP123 Senior Member

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    Just don't count on the fuel in the aft tank until you know if it's accessable. If the previous owner ran off the forward tank and has the valve to the aft tamk closed (which would account for that gauge always reading full), you're only accessing half your tankage.
  10. Capt Ralph

    Capt Ralph Senior Member

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    Please do. If you're full, you don't want to draw from one tank and return to the other and go water skiing. Many boats have different fuel manifold systems. The Post kids are really up on these things BUT previous owners, design changes, yada, yada can alter valve management. Look at the valves, think about fuel flowing THRU the engine and returning and where that return goes.
    I have witnessed so many operators returning to a full tank, AND ya know where that goes????
  11. Beau

    Beau Senior Member

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    On the 50's the forward tank is smaller about 350 and the aft is larger about 550. In an effort to save weight, unless we are on a extended run, I will leave the forward tank only about 1/4 filled and run my genny off that tank. If need be I have a transfer pump to restock the forward tank if I stay on the hook an extra day. And you definitely need to be sure that you are returning fuel to the tank(s) you are drawing from.
  12. K1W1

    K1W1 Senior Member

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  13. Dennis serras

    Dennis serras New Member

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  14. Dennis serras

    Dennis serras New Member

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    Couldn't figure out how to post a picture. I sent them to carl@yachtforum and hope they get on. Beau description looks right. Still not sure if I'm running on aft or forward tank.
    Dennis
  15. K1W1

    K1W1 Senior Member

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    If you were to click on the link I posted you should have gone to Post No 8 in the FAQ ( Available under the Rules button in the header of this page)

    It contains step by step instructions, the only difficulty you might encounter is if the photos you are trying to post are too big size wise to comply with Forum Rules
  16. Dennis serras

    Dennis serras New Member

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  17. Dennis serras

    Dennis serras New Member

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    Not seeing "manage attachments " on bottom left side of "post rely window"
    Dennis
  18. Beau

    Beau Senior Member

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    sounds like you are running off the forward tank. If you have found the adjustment valves, 2 of them, one supply one return, you can try turning the handles to their opposite positions, and see if you draw off the rear after you trace the fuel lines. If you are set up like mine, you will now draw from both tanks.
  19. K1W1

    K1W1 Senior Member

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    I guess those instructions were written before the forums OS was changed to what it is now.

    Click on reply, there is a button under the box that says "upload file" this will open a window on your PC, navigate to the image you want to up load and click on it then click on OPEN which will be a button on the lower RHS of the window that popped up, the rest is pretty self explanatory.

    The size of your files is important .

    If yours are too big download a free proggie called Pix Resizer and make them smaller then post them.
  20. YachtForums

    YachtForums Administrator

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    Here is the image I received from Dennis, resized for YF...

    Attached Files: