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  • OMC loud Clunking

    turned on boat this morning and i heard a clunk right as it cranked and it continued with the engine. its hard to hear at a low idle but its there in neutral as well as forward. didnt try reverse. it gets louder with rpm. it didnt sound like it was the engine so i took the outdrive off and gimbal and ujoints seem okay. nothing obvious by looking. any ideas what could be clunking. it was pretty loud and seemed very problematic i wouldnt not operate boat as such i could feel the vibration aswell in steering wheel when trying to get over 2k rpm the clunk would get bad ? any help appreciated

  • #2
    it would help us if we knew what OMG outdrive you have.... over the 50 decades that OMG was in business prior to them going out of business decades ago, they made a few different drives...... and each one may have different problems....

    so what drive do you have?
    and have you been keeping up with the annual maintenance per the factory manual?
    Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

    1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

    Past Boats
    1970 Wooster Hellion - Merc 9.8
    2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
    1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

    What’s behind you doesn’t matter.Enzo Ferrari

    Comment


    • #3
      Originally posted by Scott Danforth View Post
      it would help us if we knew what OMG outdrive you have.... over the 50 decades that OMG was in business prior to them going out of business decades ago, they made a few different drives...... and each one may have different problems....

      so what drive do you have?
      and have you been keeping up with the annual maintenance per the factory manual?
      its a omc cobra 1987 on a 5.7. i have kept up with annual maintenance yes

      Comment


      • #4
        If you pulled the drive off you can run the boat on the water hose by disconnecting the water feed hose at the thermostat housing and connecting a garden hose to that (may have to use a hose adapter). That way you can determine if the noise is coming from the engine or the drive. If its gone when the drive is off then you have to re-check the u joints....if they are ok, then it could be internal to the drive...if so...I'd remove the impeller housing so you can easily turn the driveshaft while someone shifts the shift rod into FWD, NEUTRAL and REVERSE to see if you get unusual noises when doing that.

        If its coming from the engine you can use a mechanic's stethoscope to try to localize it.
        1988 Four Winns 200 Horizon
        4.3 OMC Cobra

        98 Jeep Grand Cherokee 4.0 Selectrac
        07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

        "While air doesn't freeze....rust never sleeps"

        Comment


        • #5
          Originally posted by Lou C View Post
          If you pulled the drive off you can run the boat on the water hose by disconnecting the water feed hose at the thermostat housing and connecting a garden hose to that (may have to use a hose adapter). That way you can determine if the noise is coming from the engine or the drive. If its gone when the drive is off then you have to re-check the u joints....if they are ok, then it could be internal to the drive...if so...I'd remove the impeller housing so you can easily turn the driveshaft while someone shifts the shift rod into FWD, NEUTRAL and REVERSE to see if you get unusual noises when doing that.

          If its coming from the engine you can use a mechanic's stethoscope to try to localize it.
          sounds good ill try and isolate it. what kind of adapter do i need to get the garden hose to hook into the thermostat housing?

          Comment


          • #6
            Originally posted by cowlotter View Post

            sounds good ill try and isolate it. what kind of adapter do i need to get the garden hose to hook into the thermostat housing?
            Ayuh,..... A short piece of the appropriate sized hose, 'n clamps,....

            Whatever it takes,..... cob it together,.... build yer own adapter,.....

            Comment


            • #7
              Originally posted by Bondo View Post

              Ayuh,..... A short piece of the appropriate sized hose, 'n clamps,....

              Whatever it takes,..... cob it together,.... build yer own adapter,.....
              can i just shove garden hose in the water inlet tube after the power steering cooler or how close to thermostat housing does hose have to be?

              Comment


              • #8
                You could do that too just make sure it stays in place. As long as it feeds the thermo housing with water so the exhaust does not overheat. Don't want to burn up the rubber flappers at the top of the Y pipe and the rubber exhaust hoses.
                1988 Four Winns 200 Horizon
                4.3 OMC Cobra

                98 Jeep Grand Cherokee 4.0 Selectrac
                07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

                "While air doesn't freeze....rust never sleeps"

                Comment


                • #9
                  Duct tape is your friend

                  Annual inspection and maintenance includes checking the alignment
                  Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

                  1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

                  Past Boats
                  1970 Wooster Hellion - Merc 9.8
                  2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
                  1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

                  What’s behind you doesn’t matter.Enzo Ferrari

                  Comment


                  • #10
                    Originally posted by Scott Danforth View Post
                    Duct tape is your friend

                    Annual inspection and maintenance includes checking the alignment
                    alignment is good too

                    Comment


                    • #11
                      well, with a cobra, its either the alignment, the u-joints, or the gimbal bearing as the most likely sources. after that its in two input bearings in the gear box itself.
                      Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

                      1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

                      Past Boats
                      1970 Wooster Hellion - Merc 9.8
                      2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
                      1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

                      What’s behind you doesn’t matter.Enzo Ferrari

                      Comment


                      • #12
                        Originally posted by Scott Danforth View Post
                        well, with a cobra, its either the alignment, the u-joints, or the gimbal bearing as the most likely sources. after that its in two input bearings in the gear box itself.
                        the gear box in the drive? is that in the upper or lower? alignment ujoints and gimbal seem good im going to reinstall drive and try and pinpoint noise on muffs

                        Comment


                        • #13
                          Seam good?

                          What is the pattern on the alignment tool?

                          Did you spin the gimbal bearing with fingers? That will tell you the health of the bearing. It should feel smooth, and only take 2 fingers to turn

                          The u-joints should move freely, however may requre you to press out the crosses to check the bearings

                          Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

                          1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

                          Past Boats
                          1970 Wooster Hellion - Merc 9.8
                          2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
                          1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

                          What’s behind you doesn’t matter.Enzo Ferrari

                          Comment


                          • #14
                            Originally posted by Scott Danforth View Post
                            Seam good?

                            What is the pattern on the alignment tool?

                            Did you spin the gimbal bearing with fingers? That will tell you the health of the bearing. It should feel smooth, and only take 2 fingers to turn

                            The u-joints should move freely, however may requre you to press out the crosses to check the bearings
                            ran boat with the out drive attached. the noise is from the engine and much more pronounced without the outdrive off. its definitely a loud knocking or clunk. definitely internal and not something i can probably get into my self. im assuming an engine pull and internal work. what do you think and any recommendations appreciated

                            Comment


                            • #15
                              Sign up today
                              with the drive off, you have half the work to pull the motor done. disconnect the cables, exhaust, fuel lines, remove the front motor mount bolts and transom shield bolts and lift the motor out. maybe a 30 minute process

                              any 1986-1995 5.7 from a truck out of a pull-a-part salvage yard would work. just change the core plugs for brass, and use marine head gaskets. you can be back on the water for under $500

                              or have your motor rebuilt and be back on the water for about $1700
                              Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

                              1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

                              Past Boats
                              1970 Wooster Hellion - Merc 9.8
                              2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
                              1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

                              What’s behind you doesn’t matter.Enzo Ferrari

                              Comment

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