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88 OMC Cobra 5.7 Rubbing noise-gctid816649

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    88 OMC Cobra 5.7 Rubbing noise-gctid816649

    Hello Everyone,

    I have a loud "rubbing/rumbling like" noise coming from my Starboard engine when going above 2000 RPMs. I can hear the outdrive enage in gear but as soon as I go above 2000 rpm I hear this noise. If I go back down a little it stops but I cant go above 2000 rpms therefore I'm crawling on the SB side. Port is perfectly fine and both engines are completely fine. I am guessing a bad bearing somewhere, maybe the gimbal bearing? Could the lower gears be messed up? OH on land with muffs, it shifted fine and got upto high rpms but this is all happening under load of course. I can try to capture a video later this week. Any help, knowledge, or expertise would be greatly appreciated!

    Just a guess, but maybe a bad motor mount on that engine. Other wise maybe a prop slipping. Garchar
    1988 2655
    2009 Volvo Penta 5.7 300 hp DP F3s
    Twice Past Commodore
    Northwest Outboard Trailer Sailors, Eugene,OR


      Go to auto zone and get a cheap mechanics stethoscope and start listening around . You'll know when you get there usually as it'll sound entirely different, meaning uglier. It's ot a guaranteed ah ha moment but at least will zero you in. Water pumps ( front of engine one) like to growl at higher rpm so start there.

      Standard disclaimer. Lose all the bling, loose shirts sleeves and anything else you don't want ripped off including body parts. You're going to be close to fast moving belts and pullies with no conscience so be triple careful what you touch and go slow.


        See any black pieces in the bilge ?

        Ever do a drive shaft alignment.

        Ever do a gimbal bearing changeout?
        Be good, be happy, for tomorrow is promised to no man !

        1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

        '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

        Manalapan N.J


          Garchar, I'll be checking for loose or broken mounts soon! Thanks!

          Chief Alen - No Black pieces in the bilge as far as I can see, I did use my shaft alignment tool to double check alignment after replacing my shift cables, and the drive went back on as smooth as butter. Never done a gimbal which I will consider after checking the mounts and the water pump

          driz- Thanks for the suggestion, I will definitely take a look and listen! Safety first of course with anything!


            did you grease the ujoint, gimbal bearing when you had the drive out?
            Joon, Kathy, Jaden & Tristan
            Uniflite 42 AC, DD 671N
            93 3058 sold
            92 2855 (day boat)
            91 Fourwinns 205 (lake boat)
            Longbranch WA
            Life is Good


              Ruffryder - absolutely, and pretty liberally until I see grease coming out. We've had a bad week of weather and forecasts here in Jersey but I will try to get out soon so I can get a video of it.