‘95 330DA Mercruiser 454 shake at idle

Discussion in 'Sport Cruisers' started by Capt Brad, Apr 15, 2018.

  1. Capt Brad

    Capt Brad New Member

    11
    Apr 15, 2018
    Sundancer 330DA
    Twin 454 Mercruiser
    Hey guys, first spring with my new to me ‘95 330DA. Over the winter I did some general tune up work such as plugs and impellers. Fired the engines up for the first time this spring and both engines idle smooth between 1-2k rpm but any higher the boat begins to shake. Any idea what this may be? I figured it isn’t a misfire since it idles ok and like I said this is in both engines. I should note that I ran it up to ~3k rpm after about 4-5mins of low idle. Are they just cold? Is it the exhaust blowing out from the exhaust billows?
     
  2. M Prod

    M Prod Active Member SILVER Sponsor GOLD Sponsor

    420
    Oct 6, 2017
    North Vancouver, BC
    2005 Sundancer 340
    Aquapro Dinghy w/ Honda 8hp
    Kohler 5KW Genny
    Raymarine Electronics
    8.1 Horizons /V Drives
    Hard to say. Are you sure they’re running at even rpm’s? If they’re off a bit from one another, you’ll get a vibration.
     
  3. Capt Brad

    Capt Brad New Member

    11
    Apr 15, 2018
    Sundancer 330DA
    Twin 454 Mercruiser
    I only had one engine on at a time to check all sounds etc for the first fire up this year. I forgot to mention that this was all in idle. Engines were never put in drive.
     
  4. Larry

    Larry Active Member

    Oct 19, 2006
    Oakland, NJ
    2004 42 Sundancer
    Hydraulic platform
    Cockpit air
    KVH M3
    450hp Cummins
    Make sure you didn’t jump one hole on distributer, sounds like your timing could be off. I have seen many people screw this up.
     
    capt steve likes this.
  5. Saverio

    Saverio Member SILVER Sponsor

    956
    Aug 31, 2010
    Long island new york
    1995 330 DA
    Twin 454 Webber Carbs
    V drives
    Fresh water cooled
    also check that the spark plug boots are seated correctly,
    was a compression check done prior to purchase?
     
  6. Capt Brad

    Capt Brad New Member

    11
    Apr 15, 2018
    Sundancer 330DA
    Twin 454 Mercruiser
    See that's what I was wondering but when I did the plugs I did one plug at a time to ensure everything stayed in correct timing.
     
  7. Capt Brad

    Capt Brad New Member

    11
    Apr 15, 2018
    Sundancer 330DA
    Twin 454 Mercruiser
    No compression test was performed. However I had a series of sea trials and all was fine last year. But like I said, this was the first time I revved it up in neutral. I did not take her out of the dock to see if it went away under a load. Temp was only 100F so they weren't entirely warm yet
     
  8. Capt Brad

    Capt Brad New Member

    11
    Apr 15, 2018
    Sundancer 330DA
    Twin 454 Mercruiser
    Update: I found that the fuel separator filter was dated 2002.... during replacement, I did the usual dumping into a clear container and did not find water but a significant amount of solid deposits. Also while replacing the port filter, as I unscrewed the filter, gas was pouring out of the racor. Here’s my question to you guys, I’m assuming there has been little to no maintenance performed on this boat for years. Plugs were awful and as soon as I changed them this problem occurred. Do you think the new plugs were burning so much cleaner that there was not enough fuel due to the old filters? Since fuel was pouring out of the racor I’m thinking there was pressure built up between the pump and the filter. After gas poured into the bilge I spent the last of my time cleaning up the spill and never got to test it.
     
    Saverio likes this.
  9. Saverio

    Saverio Member SILVER Sponsor

    956
    Aug 31, 2010
    Long island new york
    1995 330 DA
    Twin 454 Webber Carbs
    V drives
    Fresh water cooled
    if yours is set up like mine I have 2 filter on each engine one mounted on bulkhead and another on the engine adjacent to the sea water pump. that one is a water separator. might have water trapped in it
     
  10. capt steve

    capt steve Member

    144
    May 23, 2017
    north nj
    95 330 da no genny
    7.4 merc v-drive
    +1 on this.... I had an 85 Eldorado and did a tuneup ... same thing and was not too noticable, I thought I had everything right. double checked and had 2 wires wrong on the distributor. purred like a kitten after correcting
     
  11. Capt Brad

    Capt Brad New Member

    11
    Apr 15, 2018
    Sundancer 330DA
    Twin 454 Mercruiser
    You guys will think I'm a fool but the shake was just the exhaust bubbling out from the through hull exhaust at the bottom... highly embarrassed but such a relief!
     
  12. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    506
    Jun 5, 2016
    Milton, GA
    410 Sundancer 2001
    Cat 3126 V-Drives
    I don't think your a fool at all! More like careful concerned boat owner learning a lot of new sounds, smells and proceedures to a new to you old boat.

    I've been there a lot lately myself. I think all of us will be releived that its nothing serious or expensive. Welcome to boat ownership!!
     
  13. Boater420

    Boater420 Well-Known Member

    Mar 11, 2015
    Clearwater, FL
    '97 330 Sundancer
    V-Drives
    Westerbeke 4.5BCG
    Twin Merc 454's
    Nothing to be embarrassed about. I was freaked out when I noticed that for the first time as well.
     
  14. fatcatone549

    fatcatone549 Member

    66
    Jun 1, 2011
    Brick,nj
    1999 express 21.5
    5.0
    Hi I took the boat out every thing good, on the ride back got a vibration at 900 rpm above that or below runs smooth. any ideas
     
  15. Capt Brad

    Capt Brad New Member

    11
    Apr 15, 2018
    Sundancer 330DA
    Twin 454 Mercruiser
    If you were fine at first I’m thinking you must have hit something to have chipped or slightly bend the prop that you only feel it when it’s spinning outside of idle speed. A simple feel test with your foot would feel large imperfections
     
  16. O Buoy

    O Buoy New Member

    6
    Jul 24, 2018
    1995 330 sundancer
    454 v drive
    I had a vibration at 2500 in nuetral. I found that the starboard engines motor mount had worked its way loose. The lower nut backed off all the way down. I brought the nut back up and tightened and problem solved. hopefullyit didnt mess up the shaft
     

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