Yamaha F225 3.3L ..... Thunks at 2500rpm in Forward Gear

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  • Yamaha F225 3.3L ..... Thunks at 2500rpm in Forward Gear

    This is a new one on me..... and I'm sorry to pose this question because I normally like to figure these things out myself. But I'm stumped

    Boat: 26 Southport with twin 2006 Yamaha F225 engines. 1,000 hours. Both run perfect. Never a single issue.

    History: In the past month I replaced the dry exhausts on both engines along with all 8 motor mounts. Everything came apart without issue. Everything went together without issue.

    The Problem: Put the boat in the water and engines run fine. No leaks. No issues until I get up to 2200-2900 rpm and the starboard motor will "clunk". You can feel the motor jump. You can see the engine jump as well almost 1". You can also feel the clunk in the throttle. It's very noticeable. The clunk doesn't happen below 2200 rpm nor above 2900 rpm. And only happens in forward gear. And only happens once. Never more than 1x.

    For your additional consideration, the clunking doesn't happen all the time while coming up to plane. If I go from 4000rpm down to 800 and then to neutral and back to forward gear and 4,000rpm, I don't hear/feel the clunking. Only when going from reverse gear to neutral to forward and then up to 4,000 rpm will I hear/feel the clunk at 2200-2900rpm.

    I've adjusted the gear/shift cable on both engines appropriately (disconnect the linkage at the engine, put the shift lever into a comfortable neutral position then adjust the screw-end of the cable so it easily slides over the pin. No issues there.

    Thoughts? What should I be looking for?

    I search Google on this matter and found 1 reference in 2017 on TOS from a guy who had a similar issue and he said that there was a missing "spring pin on the bottom of the bracket that caused the bracket to pivot when shifted causing it not to go far enough into gear" ..... but I'm not sure what he's referring to? On the swivel bracket? Or he might be having a completely different problem than mine.

    Thoughts?

  • #2
    I've been wracking my brain around this issue for the past few days and literally, it just dawned on me that this COULD be related to the prop. The port side has the standard Yamaha SWS 2 with the standard hub typical of 2006 era. But the starboard side prop is the newer Yamaha SWS with the SDS hub. I wonder if that "cleaver" is slipping and banging into the side of the hub????? Is that even possible? If so, why is the cleaver now slipping over when it never happened before?

    Just an idea and I could be completely wrong

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    • #3
      I bet Ken will be able to answer that, as to the prop issues.. The clunk sounds mechanical to me.. Like lower unit issues.. But, I am NOT a mechanic.. Ole or Andy should be able to help here..
      As of April 2nd, boatless for the first time in many years.
      2019 Tidewater 252 CC Twin F150's- SOLD
      2016 Tidewater 230 CC VF250 SHO- SOLD
      Mobile, Al.
      Dauphin Island, Al.

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      • #4
        I too was going to suggest to check/re-attach the shift cable on that motor, as I once helped fix a friend's boat that was doing similar ... we'd be climbing up onto plane and BAM, felt like we hit a log ...

        I know on OMCs (recall Yumster copied OMC carte blanche) you want the gear cable disconnected, with shift control lever moved all the way into reverse gear and the engine shift arm fully into reverse. Then the gear cable attachment is placed on the trunnion, and move the shift control lever to neutral and ensure it now aligns to the trunnion bracket pocket. Simple to do ... and I'd try it again, if you did not use this method, plus see below.

        Otherwise (?), you don't say if you have counter-rotating props, but if you could switch props at least just for a test ... or even borrow a spare prop for that starboard OB, that would then tell you if the problem follows the prop or the motor.
        Life is too short for an ugly boat!

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        • #5
          Originally posted by DaleH View Post
          I too was going to suggest to check/re-attach the shift cable on that motor, as I once helped fix a friend's boat that was doing similar ... we'd be climbing up onto plane and BAM, felt like we hit a log ...

          I know on OMCs (recall Yumster copied OMC carte blanche) you want the gear cable disconnected, with shift control lever moved all the way into reverse gear and the engine shift arm fully into reverse. Then the gear cable attachment is placed on the trunnion, and move the shift control lever to neutral and ensure it now aligns to the trunnion bracket pocket. Simple to do ... and I'd try it again, if you did not use this method, plus see below.

          Otherwise (?), you don't say if you have counter-rotating props, but if you could switch props at least just for a test ... or even borrow a spare prop for that starboard OB, that would then tell you if the problem follows the prop or the motor.
          Exactly ..... it feels like I've hit a small log just as I'm coming onto plane.

          I looked at the prop today and I don't see any evidence that the SDS washer has moved and it appears that the nut is very tight and cinched-down correctly.

          I can try a different prop.

          Attached is a photo of the Yamaha SDS prop as attached to the F225
          Attached Files

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          • #6
            Can you capture the "Clunk" on video?
            The noise? The engine moving?
            Engine Sales and Service
            Ph +1 954.463.1515
            Fx +1
            954.463.4904
            Toll Free: 800.622.6747

            [email protected]
            www.parkeryacht.com

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            • #7
              If the boat is out of the water, I might drop the lower unit oil and check its condition(look for metal/chunks ect). I can't imagine it coming in and out of gear and holding up very well while under a load like that.

              As Ole mentioned, a video of this occurring will help. If the engine is missing or shutting off for a split second, that could cause a reaction like that too.
              Andrew Munao Jr
              Yamaha Sales/Tech Support, SIM Yamaha
              888-231-2392 | [email protected] | simyamaha.com

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              • #8
                Thanks Andy - I did drain the lower unit oil. It was clean and free of any metal minus the small bit of normal "fuzz" that collects on the magnet. No bigger chunks of metal. The motor runs run at all RPM's including WOT for extended periods.

                I have adjusted and re-adjusted the throttle cable several times. I did notice that the Yamaha SS cable-holder bracket was not perfectly aligned with the slot on the lower-pan so I adjusted that and maybe that "fixed" the problem. Fortunately, the clunking problem has gone away.

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                • #9
                  Originally posted by GoodChance View Post
                  I have adjusted and re-adjusted the throttle cable several times.
                  ... hope you adjusted the gear shift cable too ...


                  Life is too short for an ugly boat!

                  Comment


                  • #10
                    Originally posted by DaleH View Post

                    ... hope you adjusted the gear shift cable too ...
                    Annnnnnnnnnnnnnnd, the adjustment on that STARTS at the control head end. If that isn't set right from the start, the other end will never work properly.

                    Engine Sales and Service
                    Ph +1 954.463.1515
                    Fx +1
                    954.463.4904
                    Toll Free: 800.622.6747

                    [email protected]
                    www.parkeryacht.com

                    Comment


                    • #11
                      Originally posted by Parker Yacht View Post
                      Annnnnnnnnnnnnnnd, the adjustment on that STARTS at the control head end. If that isn't set right from the start, the other end will never work properly.
                      Ouch!!!

                      BWP

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