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clanging noise on jackshaft

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  • clanging noise on jackshaft

    I have a cc25 with 454 chevy I have a clanking noise only when I am ideling when I put boat in gear the noise goes away. The noise is getting louder but while running I have no noise. The noise sounds like it is coming from the jackshaft.I need to know if Ican use boat and repair after fishing season or what repair should be done.It does not have grease fittings on it to grease the splines. Thanks ron staples
    Last edited by ron staples; 12-19-2006, 05:31 PM.

  • #2
    there are grease fittings at both ends look real hard
    2004 28 VOLVO 300 DIESELS


    • #3
      What you are probely hearing is the CV coupling at each end of the shaft ratteling when there isn't a load on it. I get it when I shut the engine down. The input (engine) and the output ends of the shaft are supposed to be missaligned about a degree to keep the CV joints active and prevent the slop in them from doing that.
      Advance, NC


      • #4
        I think it's a characteristic of the jackshaft. Mine's done it since the day it was new. Disappears as soon as it goes into gear.

        On the 10 hour check, the mechanics told me not to worry, it's pretty normal. I admit it's a bit irritating to listen to but.....

        That's my only complaint. Well, maybe one more. Why can't the fuel tanks be removed through precut floor panels? GW's have this option. I hope never to have to do that but I dread if the floor ever has to be cut up.

        Oh well. I love my boat.
        2004 Carolina Classic, Volvo 300 KAD
        2004 Boston Whaler Montauk, 90 hp Merc


        • #5

          I had a 1999 28' with yanmars and jackshafts. At idle the shafts always made the clanging noise. Once you put a load on them and increased engine rpm's 50-100 off of idle they stopped clanging. I'm with IRC, I think that is just the nature of having a jackshaft.


          • #6
            Not to change the subject but I had a 25 with this noise and it does go away when you bring the idle up, its the nature of this system , spoke to mac about it and several other people, but my friend has a 26 albie jackshafted and what a differance , albie uses a center carry bearing, like a truck set up,two short shafts instead of one long one so theres no balancing and just about no noise.IMO a better system, sorry guys, but I still own a 28 cc.If you get a chance to go to any boat shows this winter take a look at the albie set up, pretty nice.
            2004 28 VOLVO 300 DIESELS


            • #7
              Old Jackshafts

              Yeah, I have a friend that is a marine surveyor in Charleston and he once told me that albemarle was the only company that made the jackshaft system work correctly. After owning a jackshaft boat, I think there is much truth to that statement. Don't get me wrong, Classic builds one of the best boats around...but the jackshaft boats had a lot of mechanical issues. That is why I just purchased a straight inboard. I hoping that I'll get to do more fishing than fixing. With my old jackshaft boat it was the other way around.


              • #8
                Originally posted by Hey Doc View Post
                With my old jackshaft boat it was the other way around.
                I was under the impression that the jackshafts may clang but they were very reliable. Is that not so? Do they fail often and if they do is it catastrophic or more of a progressive failure where the noise gets worse and worse until you have to replace it?


                • #9
                  28 shaft

                  The shafts always make noise when they are not under load, or in gear but at idle. Other than balancing issues, I never really had any problems with the actual jackshafts. The mechanical issues seemed to be more with the mechanical gear that the shafts were coupled with.

                  I had the gimbal bearings replaced twice. The shafts still made a bunch of noise and would occasionally rub the inside portion of the stringers. Finally, had the boat yard talk to Mac and he recommended changing the gimbal house assembly that holds the shaft and the bearing. Apparently over time, the shaft forces round out the housing support structure regardless of how well you maintain your gimbal bearings. I was told that it happens with both volvo and mercuiser boats.

                  The steering components always seemed to be an issue as well. The inside steering bar flexed, allowing the drives to come out of alignment with each other. This caused a vibration at cruising speeds that was not unbearable, but certainly not good for the drive. To remedy this issue I added a high dollar racing set up tie bar in between the two drives. It fixed the vibration issue, but over time it caused the steering arm linkage to loosen on the port dive attached to the hynautic steering cylinder.

                  I'd mention the drive issues I had as well, but it is sufficient to just say they were always a problem. I had several replaced under warranty, but I could never get a new drive to last more than about 125 hours.

                  Keep in mind that all the components were new, the boat was stored on a lift out of the water, all work was performed ahead of schedule and I never pushed the boat hard. Despite all this, I always had mechanical issues with the shafts, the steering, or the drives.

                  I thiink that 25CC owners have had less trouble with their boats because the shaft system is not as long as the set up in the 28. Also, most of the 25's were not paired with the bigger diesel power. Maybe I just had a boat that was prone to mechanical failures, but I find this hard to believe given that most of the new 25 and 28 CC being produced today come with straight inboards.