1990 350 Sundancer engine knock....

Discussion in 'Classic Sea Rays' started by QT1, Jan 5, 2019.

  1. QT1

    QT1 Active Member

    470
    Oct 20, 2016
    Belair, MD
    1990 350 Sundancer, "Quality Time II". Avon rib w/ Yamaha 4 stroke. Upgraded Raymarine GPS/radar.
    7.4 Mercruisers
    . title is 1990 Sea Ray Sundancer 454 engine knock.
    I don't know if this link will work, but having the same engine knock on the starboard engine with less than 100 hours on each repowered engine. Would love to hear any suggestions. Thanks.
     
  2. hottoddie

    hottoddie Well-Known Member

    Jan 11, 2012
    Boston/Cape Cod
    1986 Sea Ray 390 EC
    Garmin 4212 Chartplotter
    Garmin 24 HD Radar
    Garmin 546s Plotter
    454 Crusaders
    Doesn't sound loud enough to be a rod or piston knock. It seemed to get louder when you moved to the starboard side. Sounds related to the valve train. If you had a stethoscope you could narrow it down but try removing the starboard valve cover to inspect the rocker arms and pushrods.
     
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  3. QT1

    QT1 Active Member

    470
    Oct 20, 2016
    Belair, MD
    1990 350 Sundancer, "Quality Time II". Avon rib w/ Yamaha 4 stroke. Upgraded Raymarine GPS/radar.
    7.4 Mercruisers
    The surveyor gave the same suggestions. I will have to wait until open season to run the engine and perform this diagnostic. Thanks for the input.
     
  4. Rusted Nut

    Rusted Nut New Member

    15
    Sep 21, 2016
    Lake Michigan
    1993 370DA
    Lots of engines
    Pull a oil sample for analysis.
    Is it the same old/hot? In gear does the sound change?
     
    QT1 likes this.
  5. QT1

    QT1 Active Member

    470
    Oct 20, 2016
    Belair, MD
    1990 350 Sundancer, "Quality Time II". Avon rib w/ Yamaha 4 stroke. Upgraded Raymarine GPS/radar.
    7.4 Mercruisers
    If I remember correctly, it's the same in either temperature. That is a good idea about collecting a oil sample. Thanks
     
  6. Espos4

    Espos4 Active Member

    698
    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    Surveyor?
    Are you buying or selling this boat?
    Or have you had it for a few years?
     
  7. Socks

    Socks New Member

    25
    Jan 7, 2019
    1983 Sea Ray 270 Sundancer.
    Twin 5.0L (305 ci) Mercruisers
    It sounds to me like a rocker is too tight -- I don't claim to be a mechanic -- but in adjusting hydraulic rocker, we tighten down until knocked and back off (assuming these are hydraulic) this sound like that type knock. ---

    Good luck
     
    QT1 likes this.
  8. QT1

    QT1 Active Member

    470
    Oct 20, 2016
    Belair, MD
    1990 350 Sundancer, "Quality Time II". Avon rib w/ Yamaha 4 stroke. Upgraded Raymarine GPS/radar.
    7.4 Mercruisers
    Tonight I will take a pic of the survey page showing the compression reading. Thanks Socks for the info. I'm taking all advise to work on this. I must say, the boat runs fine.
     
  9. QT1

    QT1 Active Member

    470
    Oct 20, 2016
    Belair, MD
    1990 350 Sundancer, "Quality Time II". Avon rib w/ Yamaha 4 stroke. Upgraded Raymarine GPS/radar.
    7.4 Mercruisers
    Bought the boat. Picked it up in November. Sold my 300 Weekender.
     
  10. Espos4

    Espos4 Active Member

    698
    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    I agree, sounds like valve train noise. I'm not familiar with your particular application, but if its an adjustable valvetrain, one or more valves may need to be adjusted.

    If it's non-adjustable, you may have a bent push rod, collapsed lifter or even a worn camshaft.

    Remove the valve covers and look for excessive play in the rocker arm/push rod. You'll need to rotate the engine by hand, as you need to check each valve when it is completely closed.
     
    QT1 likes this.
  11. QT1

    QT1 Active Member

    470
    Oct 20, 2016
    Belair, MD
    1990 350 Sundancer, "Quality Time II". Avon rib w/ Yamaha 4 stroke. Upgraded Raymarine GPS/radar.
    7.4 Mercruisers
    Keep in mind, the engines were reconditioned with about 100 hours on them as of 9/17.
     
  12. Rusted Nut

    Rusted Nut New Member

    15
    Sep 21, 2016
    Lake Michigan
    1993 370DA
    Lots of engines
    Congrats on the new boat. I would reset all valves. Are you planning on adjusting the valves?
     
  13. QT1

    QT1 Active Member

    470
    Oct 20, 2016
    Belair, MD
    1990 350 Sundancer, "Quality Time II". Avon rib w/ Yamaha 4 stroke. Upgraded Raymarine GPS/radar.
    7.4 Mercruisers
    I. will wait until the boats back in the water, then I plan on making an appointment to the place the po had the motor work done.
     
    Rusted Nut likes this.

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