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  1. #1
    Join Date
    Feb 2011
    Location
    Newport, RI
    Boat
    Sea Ray
    Details
    2003 Sundancer 460
    Engine(s)
    Cummings 8.3 6CTA
    Posts
    101

    Cummins 480CE engine vibration

    Hey All,

    I have a 2003 460DA with Cummins 480CE's aboard. I have put 800 hours on the engines in 12 months with no issues. Recently, when I run at about 2900 RPMs, I get a hard vibration and a drop in RPMs for 1-3 seconds, then it subsides. It then gets more frequent. If I continue, it can be almost a constant thing.

    I ran an hour yesterday at 2200 RPMs with no hard vibration, but I can feel a small vibration with no RPM loss. I pushed it to 2900 just to see if it was still there and it happened again.

    I have checked the wheels for obstructions, but found none. I did check the tranmission fluid level and it is good.

    Thoughts?

  2. #2
    Join Date
    Jul 2007
    Location
    1000 Islands
    Boat
    Sea RAy
    Details
    420 Sundancer
    Engine(s)
    Cummins
    Posts
    85

    Re: Cummins 480CE engine vibration

    Those engines are are rated for 2650 rpms....seem like you are running them on the high side. I have 480ce's and run them at 2100 - 2150.
    Branch Office
    2005 420 Sundancer
    480CE Cummins
    1000 Islands, NY

  3. #3
    Join Date
    Oct 2006
    Location
    Middle Tennessee/NW Florida
    Boat
    Sea Ray & a Boston Whaler Dauntless (75hp Merc)
    Details
    1996 450DA
    Engine(s)
    3116 Caterpillars
    Posts
    8,547

    Re: Cummins 480CE engine vibration

    There is a known problem of the damper separating from the coupler on C Series Cummins. You probably need to get a Sea Ray dealer or Cummins technician on the boat to be sure what is going on. One clue is black dust on the front of the transmission housing where it bolts to the engine. The black is the rubber disintegrating where the 2 parts of the flywheel are vulcanized together.
    Frank

  4. #4
    Join Date
    Feb 2011
    Location
    Newport, RI
    Boat
    Sea Ray
    Details
    2003 Sundancer 460
    Engine(s)
    Cummings 8.3 6CTA
    Posts
    101

    Re: Cummins 480CE engine vibration

    Quote Originally Posted by 1000islander View Post
    Those engines are are rated for 2650 rpms....seem like you are running them on the high side. I have 480ce's and run them at 2100 - 2150.
    My bad....The problem is at 2290-2300 RPMs.

  5. #5
    Join Date
    Feb 2011
    Location
    Newport, RI
    Boat
    Sea Ray
    Details
    2003 Sundancer 460
    Engine(s)
    Cummings 8.3 6CTA
    Posts
    101

    Re: Cummins 480CE engine vibration

    Quote Originally Posted by fwebster View Post
    There is a known problem of the damper separating from the coupler on C Series Cummins. You probably need to get a Sea Ray dealer or Cummins technician on the boat to be sure what is going on. One clue is black dust on the front of the transmission housing where it bolts to the engine. The black is the rubber disintegrating where the 2 parts of the flywheel are vulcanized together.
    Thnaks Frank. I will look for the dust and note this issue when I call the technician.

  6. #6
    Join Date
    Apr 2012
    Location
    Tampa
    Boat
    Sea Ray
    Details
    390 Motor Yacht
    Engine(s)
    Cummings 480CE's
    Posts
    19

    Re: Cummins 480CE engine vibration

    I have a 390MY with 480CE's on them. Not sure if your boat is in fresh water or not, but I would make sure there has not been any buildup on the props. That can definitely send a vibration through your boat. Also, depending on the size of your boat, there is a harmonic frequency at a certain RPM that will send shudders through your boat... kinda like a vibration. On my boat it is right around 1900 RPM... I tend to run mind right around 2000 RPM.

    I would also check to see if you are getting any water in your bilge. That could mean you have a bit of a bent shaft and water is coming in past the seals. Hope this helps.

  7. #7
    Join Date
    Nov 2006
    Location
    East Coast
    Boat
    Sea Ray
    Details
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    Engine(s)
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    Posts
    7,837

    Re: Cummins 480CE engine vibration

    IMO, it could be a fuel related issue. Have you tried changing your fuel filters (primaries and racors)? How's the racor bowl looking? It could be just a bad fuel load.

    2005 420DB "Inspiration" - 420/44 DB Owners Club
    Previously Owned: 2004 320DA "Boat A Bing" || 2001 240DA "Very Delicately" || 1997 175BR "Another Toy"

    Live a good life and in the end, it's not the years in a life, it's the life in the years. - Abraham Lincoln

  8. #8
    Join Date
    Oct 2006
    Location
    Middle Tennessee/NW Florida
    Boat
    Sea Ray & a Boston Whaler Dauntless (75hp Merc)
    Details
    1996 450DA
    Engine(s)
    3116 Caterpillars
    Posts
    8,547

    Re: Cummins 480CE engine vibration

    How would dirty fuel filters cause a vibration?
    Frank

  9. #9
    Join Date
    Nov 2006
    Location
    East Coast
    Boat
    Sea Ray
    Details
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    Engine(s)
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    Posts
    7,837

    Re: Cummins 480CE engine vibration

    It's just the way I read the OP's post. He gave us very little details, but stated that his running gear is fine. I'm just thinking that if an engine has fuel issue it might vibrate at different RPMs due to starvation (like a misfiring gas engine).

    From my experience if a prop is damaged then the vibration is more noticeable when engine is loaded the most, which would be getting out of the hole. Unless we get more details from OP on running gear and/or other symptoms it won't be possible to determine the true cause, IMO.

    2005 420DB "Inspiration" - 420/44 DB Owners Club
    Previously Owned: 2004 320DA "Boat A Bing" || 2001 240DA "Very Delicately" || 1997 175BR "Another Toy"

    Live a good life and in the end, it's not the years in a life, it's the life in the years. - Abraham Lincoln

  10. #10
    Join Date
    Oct 2006
    Location
    Middle Tennessee/NW Florida
    Boat
    Sea Ray & a Boston Whaler Dauntless (75hp Merc)
    Details
    1996 450DA
    Engine(s)
    3116 Caterpillars
    Posts
    8,547

    Re: Cummins 480CE engine vibration

    Nope.......a diesel either fires or it doesn't. There isn't any misfiring. If filters are clogged, either the engines slows down, or it sucks air into the fuel system. If it sucks air in, cylinders don't get fuel because air is compressible so the injectors won't open.
    Frank

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