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DD 6-71 Governor type/model?

Discussion in 'Technical Discussion' started by P46-Curaçao, Mar 28, 2016.

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  1. P46-Curaçao

    P46-Curaçao Member

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    For my 1981 Detroit 6-71 SB engine, I want to order a rebuild Governor, but I'm wondering what type/model it is and if LH-RH is an issue? Also is it limiting or variable speed?
  2. P46-Curaçao

    P46-Curaçao Member

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    Here a picture

    Governor.jpg
  3. rcrapps

    rcrapps Senior Member

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    Usually a single weight, variable speed, mechanical governor.
    The serial number or tags will offer the best data.

    Why are you wanting to replace it?
  4. P46-Curaçao

    P46-Curaçao Member

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    After replacing 3 bearings, it still has a problem, so I exchanged it with another one I borrowed from a friend, and it runs fine, so better get a rebuild one for $2-300.

    The only number I see is 5183313LH
    Last edited: Mar 28, 2016
  5. rcrapps

    rcrapps Senior Member

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    '81 serial numbers for 671s started at 6A414833. look for a number starting with 6A.

    May be the marinizers (JT, Convington, etc) serial number

    3 bearings and what problems? There are some adjustments.
  6. P46-Curaçao

    P46-Curaçao Member

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    Ok, I though you meant part nr... the engine serial number is 6A415132 and it's Detroit marinized, not JT etc.

    The engine doesn't start without some extra throttle, and rpm goes up and down when cold, and idle RPM must be set at least at 700, normal is 600. With the borrowed governor, everything works like normal, my mechanic told me there is a 4th bearing somewhere in the bottom, that they can't renew...

    Buying a remanufactured one looks like the best solution to me...
  7. rcrapps

    rcrapps Senior Member

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    Those are usually adjustable symptoms.
    Possibly, the loaner governor was already closely adjusted. Likely the next (used or rebuilt) will need to be set up and adjusted in anyway.

    When running, you set the throttle to 1600 rpm and it stays there, there in not a governor issue.
    If it hunts for idle, the rack is binding or the buffer screw needs a twist.
    A non running 2 stroke, the rack is open when not running. If you have to open the throttle to start, the rack is binding.
    A binding injector may cause the same symptoms.

    Of course, I'm not there hands on. There could be some drag (lock up) in the governor that may cause some issues. Not to say it's not possible, I've never had my hands or eyes on it before.

    Just be careful when throwing money at a problem. You could induce new symptoms.

    ,rc
  8. P46-Curaçao

    P46-Curaçao Member

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    Thanks Ralph, will do the 1600 rpm test today, let's see what happens.
  9. rcrapps

    rcrapps Senior Member

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    1600 was my good example number. If the governor holds any same rpm up and down hill (swells), then it's governing. *
    The governor holds the engine speed as directed. It does not hold the throttle lever in place.
    If your throttle lever moves while running, there is another adjustment for that.


    *Hence the term variable speed, You set any engine speed, the governor will hold it there.
    Last edited: Mar 29, 2016
  10. K1W1

    K1W1 Senior Member

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    An MTU guy told me that once while doing a course but the commissioning Techs could not demonstrate this phenomenon during the initial or subsequent (and there were many) sea trials.
  11. P46-Curaçao

    P46-Curaçao Member

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    Not able to RPM test today, but found the Reliabilt part# R-5144137 (6-71 A/B, Single Weight Variable Speed , LH model)

    5144137.jpg

    New $2,459.78 rebuilt around $ 900,- (not 2-300 as stated before ;-)
  12. rcrapps

    rcrapps Senior Member

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    After replacing the governor, there is about a half dozen adjustments to be made after the control rod and racks are proved smooth and not binding. This may require the valve cover removed. A floating, smooth and free complete travel on the control tube is important before any governor adjustments are done.
    Light her up (with vice grips on the shutdown lever for added leverage), Find some kind of course idle, course throttle assist spring adjustment and shim up the WOT / Max rpm / no-load rpm.
    Then fine adjust the throttle assist spring, idle, idle buffer. Then put on the water skis and go.
    Details are in the DDC manual less the vice grips.

    No stuff, Big set of vice grips on that shut down lever is important just in case....
    Last edited: Mar 29, 2016
  13. rcrapps

    rcrapps Senior Member

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    If there is not a core return required, mail the old one to me.
  14. rcrapps

    rcrapps Senior Member

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    Off of his engine of from a spare shelf?
  15. P46-Curaçao

    P46-Curaçao Member

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    From his engine with same spec's as mine...
  16. rcrapps

    rcrapps Senior Member

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    Now that's a friend.
  17. P46-Curaçao

    P46-Curaçao Member

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    Small Island, some friends, and even more old DD...;-)
  18. Loren Schweizer

    Loren Schweizer YF Associate Writer

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    Hi--
    It might be worth your while to subscribe to Boats and Harbors in order to source old 71-Series parts. I believe they are out of Crosby, TN.
    BTW, I enjoyed a visit to your Curacao Yacht Club twice back in the '80s...helped deliver a 33 Bertram gas boat to a notable OBGYN with an amusing nickname.
  19. P46-Curaçao

    P46-Curaçao Member

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    Thanks Loren, I will check Boats and Harbors out!

    If I'm not mistaking, the 33ft Bertram is owned by a Yamaha outboard mechanic now...
  20. Matt Hintze

    Matt Hintze New Member

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    Left hand, idle at 500-900 rpm, if it on J&T built engine, it will be turbo charged, and it is a dual weight. There is a person you can find in Harbors and Freight Magazine and he rebuilt my for $650.

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