Cummins Marine Diesel Repower Specialists › Forums › Cummins Marine Engines › 2007 QSM 11 Surface Rust Valves 500 Hours

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  • August 21, 2019 at 11:33 pm #77125

    Richard Lynch
    Participant
    Vessel Name: Kathiann
    Engines: QSM 11
    Location: MD
    Country: United States

    During a routine valve adjustment on both engines our mechanic found surface rust on the valves for both engines. He cleaned them both up and suggested we send the oil out for testing in 30 hours or so. Our current oil samples show clean however the previous owner had recently changed the oil (within 10 hours) so we know that probably is not a good indicator.

    Thoughts? Suggestions?

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  • August 24, 2019 at 6:11 am #77210

    Steve Lewis
    Participant
    Vessel Name: Just Us
    Engines: Cummins 480CE
    Location: Marblehead, OH
    Country: USA

    Advice

    Based on the reported performance of ~30mph @ 2000rpm burning 22GPH I would probably look into having the props tuned a bit. Read the following and then my advice will make sense. The last sentence says it all

    Propping the Cummins Marine QSM 11 to Prevent Exhaust Issues

    take an inch or two out of the prop pitch and that should get your fuel burn down under the recommendation and that will extend the life of your exhaust manifolds. You have speed to spare so a little sacrifice of forward motion to make your engines happy is worth it in my book………

    Since you are in brackish to salt water have all of the sea water sides of your attachments serviced as well. Pumps, Coolers, Exhaust etc…… Lots of good stuff to read about all of that. Maybe even post some pictures so that we can see your engines and engine compartment. Pictures are worth thousands of words.

    August 22, 2019 at 5:37 pm #77178

    Richard Lynch
    Participant
    Vessel Name: Kathiann
    Engines: QSM 11
    Location: MD
    Country: United States

    Thank you much for the responses. Should I be concerned? Or do I just need to use the boat and give it good service? We are typically 100+ hours per year with long runs (2hrs) and service regularly

    August 22, 2019 at 5:33 pm #77177

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    Looks to me that there has been a lot of Dock warmups over the last few years.

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    Richard Lynch
    August 22, 2019 at 5:29 pm #77175

    Richard Lynch
    Participant
    Vessel Name: Kathiann
    Engines: QSM 11
    Location: MD
    Country: United States

    I am just taking delivery tomorrow but previous owner ran short trips (30 minutes) up the Chesapeake bay. Always ran 2000 rpmā€™s burning 22gph running 29-30mph at 75-80 % load is what he told me

    Has not used the boat 50hours in the last 12 months

    August 22, 2019 at 5:21 pm #77174

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    In the last 50 engine hours, how much fuel have you used? Planing hull?? In the last 50 hours how how much time on plane above 1700 rpm or so?? Do warm or try to warm your engine up at the dock??

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    Richard Lynch
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