very rough vibration

Discussion in 'Jet Drives' started by barnette2121, May 12, 2015.

  1. barnette2121
    Joined: May 2015
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: valley alabama

    barnette2121 New Member

    Hey guys and gals. I'm stumped and could really use so expert advice. Just purchased a 1996 sea ray sea rayder f16. Has the mercury 120 4cyl. In it. Motor runs great was out on the lake a couple days ago and was running pretty good but all of the sudden there was a really bad vibration. Sounded like it was in the motor but motor seemed to be running fine. The higher the rpm the worse it got. Took the pump off today and everything looks pretty good. Had oil in it but noticed there was some wear on the shaft right in front of the nut that holds the impeller on. Please help I'm at a stand still and don't know what to look for or where to go from here. Also there is some sponge looking thing to the left of the pump between the pump and the boat. Not sute if that is of concern but just incase. Thanks In advance.
     
    barnette2121, May 12, 2015
    #1
  2. gonzo
    Joined: Aug 2002
    Posts: 16,802
    Likes: 1,721, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Is that the mercury outboard on sterndrive? Post some pictures of the sponge to see what it looks like.
     
    gonzo, May 12, 2015
    #2
  3. barnette2121
    Joined: May 2015
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: valley alabama

    barnette2121 New Member

    I was told its the mercury outboard motor. Will post a pic later.
     
    barnette2121, May 12, 2015
    #3
  4. Oleboynow

    Oleboynow Previous Member

    sounds like a bent shaft or prop out of balance, , grab the prop and see if if flexes in the brg housing
     
    Oleboynow, May 13, 2015
    #4
  5. gonzo
    Joined: Aug 2002
    Posts: 16,802
    Likes: 1,721, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    A spun hub may also do that. Also can be a fuel/carburetors problem.
     
    gonzo, May 13, 2015
    #5

  7. FAST FRED
    Joined: Oct 2002
    Posts: 4,519
    Likes: 111, Points: 63, Legacy Rep: 1009
    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    All engines have a natural vibration period.

    The mfg attempt to balance the parts so the vibration is outside the engines normal operation RPM.

    If it is smooth at a slightly higher RP< go for it.
     
    FAST FRED, May 28, 2015
    #6
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