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Cummins QSM-11 information

Discussion in 'Engines' started by clovehitch, Feb 15, 2022.

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  1. clovehitch, Feb 15, 2022
    #1
    clovehitch

    clovehitch Member

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    Looking into a purchase of a 2003 vessel with twin Cummins QSM-11. Shows under 700 hours but was last serviced in 2013. Any advice would be appreciated about what to look for with these engines and/or any issues that anyone might have had with engines that have sat for a couple of years.
  2. SeaEric, Feb 15, 2022
    #2
    SeaEric

    SeaEric YF Historian

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    After coolers service. If they need replaced they are really expen$ive.
  3. clovehitch, Feb 15, 2022
    #3
    clovehitch

    clovehitch Member

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    Thank you. I have not heard that. I have heard some talk about the QSM-11 having wet or dry exhaust and turbos. Do you know if QSM-11 engines could have either wet or dry systems?
  4. BigChief, Feb 15, 2022
    #4
    BigChief

    BigChief Member

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    I know some of the QSM 11s are dry exhaust systems meaning there is no antifreeze circulating through the exhaust manifold or turbo and they do run very hot and are prone to exhaust manifold gasket leaks and turbo mounting problems Which happens when the engines are overpropped and overloaded.
    There is quite a bit of information out there regarding these issues
    Good luck
  5. clovehitch, Feb 15, 2022
    #5
    clovehitch

    clovehitch Member

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    Thank you
  6. Jack P, Feb 20, 2022
    #6
    Jack P

    Jack P New Member

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    I had a pair for 8 years only problem was one turbo and exhast manifold gaskets. I understand Cummins knows about the exhaust gaskets and now has a discounted kit for the repair. Otherwise they are great engines good luck
  7. Capt Ralph, Feb 20, 2022
    #7
    Capt Ralph

    Capt Ralph Senior Member

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    They are great engines.
    Dry exhaust wrapped in heat shielding material.
    Just keep the exhaust temps down to save the manifolds and gaskets.
    The easiest way to do this is don't load the engines hard and maybe take some (some) pitch out of the propellers.
    There are some good articals from Tony on this.

    During your sea trials, make sure the engines make WOT Rpm plus 250 - 300.

    Example;
    The 600 to 660 HP tuned versions turn 2300 @ WOT.
    I would recommend WOT @ 2550-2600 Rpm with medium weight on the boat.

    Up to 550 HP tune turned 2100 @ WOT.

    By the way, I think you can search YF and discover that we recommend an extra RPM margin to all marine engines.

    Keep us up on your shopping trials and survey.
  8. clovehitch, Feb 20, 2022
    #8
    clovehitch

    clovehitch Member

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    Thank you for this information.
    I'll post more if I proceed with the survey and purchase.
  9. Capt J, Feb 20, 2022
    #9
    Capt J

    Capt J Senior Member

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    I also have heard the exhaust manifold issue and hear they not only warp but crack. But that's REALLY bad when they're recommending them be 250-300 rpms underpropped. I've been told to keep fuel consumption at 20 gph or less at cruise and you'll be fine on the manifolds.
  10. mapism, Feb 20, 2022
    #10
    mapism

    mapism Senior Member

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    I'm not familiar enough with these engines to tell for sure, but is that even possible?
    Most diesels I came across would hit the high idle governor limit at 100 or 150 rpm above their max rated rpm.
  11. clovehitch, Feb 20, 2022
    #11
    clovehitch

    clovehitch Member

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    Thank you
  12. Capt Ralph, Feb 20, 2022
    #12
    Capt Ralph

    Capt Ralph Senior Member

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    20gph per engine is only (approx) 400 HP per engine. That sux with the later HOs.
    You will probably run here 90% anyway, just hate the idea to worry when you want/have to open them up.
    A pyrometer could help but hard to decipher when/where that critical moment is unless you crack one and have the EGT recorded. Not sure anybody knows the temp threshold.
    Still great engines.
  13. Capt Ralph, Feb 20, 2022
    #13
    Capt Ralph

    Capt Ralph Senior Member

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    So, the question is; Are you a fast cruiser or a slow cruiser?
    Cummins fuel system can not be beat. High HP engines run at slow speed is O K.
    So, cruising all day at hull speed, Big Smiles everywhere.
    Cruising on step, not overloading the engines is fine also.
    Think of that ole manual gear car/truck in high gear pulling a load at low speed. Avoid this. Sadly, one speed gear on most boats.
    At hull speed or on top of the torque curve to start.
  14. Captain Estee, Mar 2, 2022
    #14
    Captain Estee

    Captain Estee New Member

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    This might help you out. It's you GPH at certain RPM's That I have been following. Yes I'm a little slower but what's the hurry?

    Attached Files:

  15. Charlesocean, Mar 2, 2022
    #15
    Charlesocean

    Charlesocean New Member

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    Look up seaboard marine. Tony Athens has tons of info on the qsm 11 engine. It is a rock solid engine. You can read from Tony how to keep them that way also. No more maintenance than any other marine engine.
  16. clovehitch, Mar 3, 2022
    #16
    clovehitch

    clovehitch Member

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    Thanks to all for the information.
    I've decided to pass on this vessel based upon all the information I have received.
  17. Capt Ralph, Mar 3, 2022
    #17
    Capt Ralph

    Capt Ralph Senior Member

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    You would consider our comments bad news?
    Just for feedback, What really turned you off?
  18. clovehitch, Mar 3, 2022
    #18
    clovehitch

    clovehitch Member

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    All comments were positive and not bad news.
    A couple of issues turned me away. One was "re-proping" to meet the curve. Second was in talking with Cummins Technicians there are numerous concerns regarding the dry turbos and exhaust manifolds along with after cooler issues. The last was the amount of time the vessel sat with little use and the engines not being serviced in the past 9 years.
    All information received stated the engines are solid but I am interested in cruising above displacement speeds.
    Thanks again to all who provided their insight about these engines.