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Low load operation

Discussion in 'Engines' started by Dan balmer, Jul 6, 2020.

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  1. Dan balmer

    Dan balmer Member

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    Port Canaveral,fla
    Hi all. Was wondering about low load operation for economy to the Bahamas on 50 Post with Mtu at idle speed of 7 at 1.8 mph and the ramifications of doing that. That’s 1.8 nmpg
  2. BRyachts

    BRyachts Member

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    Shouldn't be an issue for a short run like that. Maybe bump them up to normal cruise speed occasionally, or a short hard run just before pulling into port to get the temps and pressures up to normal for a bit.
  3. Dan balmer

    Dan balmer Member

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    I wanted to make sure that I m not pursuing a false economy whereby the charge air coolers or turbos or whatever are compromised somehow. I just got thru removing and sonically cleaning the coolers which were quite contaminated and that job on these MTU was quite the project.
  4. Pascal

    Pascal Senior Member

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    Many boats are often run at hull speed. As long theyb stay at operating temp, it’s fine. I usually run them up to cruise for 15-20 minutes after a long slow day.
  5. Capt J

    Capt J Senior Member

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    I believe you have 8v183's. I wouldn't run them at dead idle all of the way to the bahamas, but you should be fine at 800 rpms and even better at 1000 rpms. Then again I bet your boat spent many a day trolling around at idle rpm's with ballyhoo's behind the boat. You'll get great mileage at 1000 rpms but even better at 800 rpms. I'd run them 800, then run them up to rated fast cruise for 30 minutes every 6 hours.
  6. mapism

    mapism Senior Member

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    The exact model (TE92/657hp or TE93/756hp) might make some difference.
    I agree with your suggestion of avoiding dead idle with the latter, but for a whole bunch of reasons, I wouldn't mind doing that with the former.
  7. Dan balmer

    Dan balmer Member

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    Engines are 8/183/93@756 hp. Thanks for your responses I have a clearer understanding of how to view this idea.
  8. Bill 32

    Bill 32 New Member

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    I tried it years ago when fuel was high. If you're going perpendicular to the Gulf Stream you will end up just pointing into it and not making much progress and hence not saving much fuel.
  9. NYCAP123

    NYCAP123 Senior Member

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    Very good point. From Miami you can just head a bit south and play the current, but from Canaveral he'll be fighting it the whole way. Bring the throttles up.
  10. JWY

    JWY Senior Member

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    What does MTU have to say about your specific engines? Maybe also call the engine surveyor who surveyed them for you at purchase.
  11. Soulstice

    Soulstice Member

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    The 50 Post is a SportFish with engines normally designed for long days of trolling at hull speed. I would just agree as others have said, bring the RPM’s up and run the engines at a cruising speed for 20 min or so before you get to your destination. This will heat your turbo’s up, clean out soot build up, etc.
  12. Capt J

    Capt J Senior Member

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    On the way back with the current it would be good to go slow.