boat vibration

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  • boat vibration

    looking for some input regarding a resonating vibration that occurs when on plane below 3800 rpm. Just a little background, when I took delivery of the boat the engine was mounted on the third hole down and had a 3 blade rebel prop. With this setup which came from the manufacture the boat had a vibration that would rattle the back door and just didn't fell right below 4000 rpm. If I tried to trim the boat it would pull hard to the right. As recommended by the manufacture the engine was lowered to the second hole from top. This helped with the prop blow out in turns but the vibration remained. I changed the prop to a 4 blade which made a huge difference with the vibration.

    I still have a resonating vibration below 3800 RPM which is especially noticeable when the gas tank is less than half full. (drum effect). now that the boat is out of the water a measured the ventilation plate height above the keel which is 2 5/8". that seems high to me. I only have one hole to go which should get me down another 3/4" which I will have done in the spring. I'm thinking with this ventilation plate height the prop is ventilation causing the resonation vibration

    Any input would be appreciated


    tjm


  • #2
    What engine, what boat?
    Engine Sales and Service
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    954.463.4904
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    oparker@parkeryacht.com
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    • #3
      2017 Robalo R227 dual console with Evinrude G2 250

      tjm

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      • #4
        All motors (not just OBs) will have an RPM range where they may cause excessive vibration throughout the hull or vehicle. That said, on boats it usually is within the RPM range while powering up on to plane, so as to minimize any 'felt effects'.

        OB Height - You do NOT judge the depth or height of a OB that way ... you need to run the boat and while trimmed out properly, have someone else steer and stick your head over the stern. Ideally you want the OB ventilation plate to be at or just above the surface of the water exiting the hull; you want it above the flow - not in it.

        Click image for larger version  Name:	OB-Height.jpg Views:	1 Size:	46.4 KB ID:	50737
        If permissible here ... here is a link describing it with pictures: http://www.veradoclub.com/index.php?topic=137.0

        NOTE - Setup in this way, you WILL need to trim the OB in to take a tight turn! This is correct for best overall running efficiency. Some props (4-blades or premium raked/cupped wheels) can be run higher than stock/OEM props. Note the my #1 boating pet peeve is that Dealers mount the OBs way too deep. They don't want to deal with Customers coming back and saying "My motor vents whenever I turn the boat ..." and they sure aren't concerned with your performance or fuel efficiency.

        FWIW my #2 boating pet peeve is that Dealers mount the wrong prop! But alas, not all of them are as experienced as Ken from PropGods!

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        • #5
          If you have a picture of the back of the boat with the engine down, that will help, depending on whether it's a straight transom or a Euro style, and where the engine is in relation to the actual keel, determines the engine mounting height.
          Engine Sales and Service
          Ph +1 954.463.1515
          Fx +1
          954.463.4904
          Toll Free: 800.622.6747

          oparker@parkeryacht.com
          www.parkeryacht.com

          Member of the MSHS Group

          Comment


          • #6
            Parker
            thanks for the reply I will take some pic's during the weekend. just some added information

            The boat as setup is not able to run a 3 blade prop without very noticeable vibration below 4000 rpm
            Prop does ventilate in turns
            When this boat is rigged with a Yamaha 200 the ventilation plate is listed as 1/2" above keel by Yamaha
            Evinrude did a performance report on the center console version of my boat with a 200hp g2 and they set the engine on the first hole

            When you look over the transom when on plane the ventilation plate is clear of the water as it was when the engine was mounted on the 3rd hole down. visually did not notice much difference between the 2nd and 3rd hole

            thanks

            tjm


            Comment


            • #7
              First place to start is confirming the set-up is to factory specification. We spend many hours on the water optimizing the set up. Depending on the boat, we are talking about a specific combination of engine height, toe-in, propeller, and trim parameters.

              Some dealers (usually older service oriented places) understand set-up, and the know how to tweek something to fit an individual need. Most however don’t have experience in this area, and do as much harm as good.

              First, make sure it is all to spec. Second, make sure you haven’t done something really odd to weight and balance. (People load the oddest stuff on boats). Third, confirm you haven’t mounted some big honking transducer or pickup on the transom hosing up water flow. Go run the boat.

              If it’s still not right, send us a photo and several of us will weigh in.

              Comment


              • #8
                2017 Robalo 227DC W/Etec

                Was this a Robalo package rigged by Robalo ?

                If this was purchased as a package from Robalo then the dealer should be involved with this and Robalo if needed as well

                So.........................................??????? ??????

                Robalo dealers are always one of the larger dealers in the area and well equipped dealers
                Robalo is very active as to customer service and demands same from their dealers
                When I ran a Robalo dealership and a complaint or question reached Robalo with a customer's issues unresolved I'd have a call from the Big Kahauna of Robalo instantly

                I'm wondering why this is on our forum for help which of course we're delighted but I cant help but ask where's the selling dealer in this?

                Please understand that all of us at BOB want questions and want to help and encourage it
                I do wonder what Robalo and/or the dealer says about it

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                • #9
                  Mike I will have to disagree with you regarding Robalo or Robalo dealers at least the one here in NJ. The dealer has been awl from day one. They sold me this boat telling me they were taking on Evinrude then when I turned over a check they told me to go find an Evinrude dealer to handle any issues. They had to have an out of state dealer register my engine for warranty with BRP. As a result no pre delivery inspection and setup was performed on the engine. The bottom line is it cost me around $1500 to make the boat usable. I eventually got reimburse for the repairs but let me tell you it was not easy to get. And yes this engine was rigged by Robalo. There were quite a few warranty issues on the boat not related to the rigging which I had to take care of as well because the dealer would not perform the repairs

                  The dealer and Robalo are out of the picture at this point. I tried to contact Robalo several times with out any reply. they only deal with there dealers so if you have a bad dealer your out of luck. Its the way they roll

                  Just my experience


                  Did not come here with the purpose of blasting Robalo, just looking for info so I can understand and possibly correct the resonating vibration.


                  tjm

                  Comment


                  • #10
                    Originally posted by tjm View Post
                    Mike I will have to disagree with you regarding Robalo or Robalo dealers at least the one here in NJ. The dealer has been awl from day one. They sold me this boat telling me they were taking on Evinrude then when I turned over a check they told me to go find an Evinrude dealer to handle any issues. They had to have an out of state dealer register my engine for warranty with BRP. As a result no pre delivery inspection and setup was performed on the engine. The bottom line is it cost me around $1500 to make the boat usable. I eventually got reimburse for the repairs but let me tell you it was not easy to get. And yes this engine was rigged by Robalo. There were quite a few warranty issues on the boat not related to the rigging which I had to take care of as well because the dealer would not perform the repairs

                    The dealer and Robalo are out of the picture at this point. I tried to contact Robalo several times with out any reply. they only deal with there dealers so if you have a bad dealer your out of luck. Its the way they roll

                    Just my experience


                    Did not come here with the purpose of blasting Robalo, just looking for info so I can understand and possibly correct the resonating vibration.


                    tjm
                    I very sorry to hear you had a bad experiance
                    That's very unusual and I am very sorry to hear it

                    Wasn't trying to pass the buck just thought that your dealer should be involved which would be, I think, a normal thought

                    Ok, with all of that said and now a better understanding of it all, how about a BRP tech rep?

                    And not to continue to throw salt on the wound, I'm extremely surprised that Robalo didn't satisfy you

                    That's really not how they operate and it saddens me

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                    • #11
                      Here are some photo I took last night. One thing that concerns me is the location of the raw water intake which if you zoom in on photo right is 8" from keel to center of the intake. I've look at other same model new Robalo's and they have them mounted in the same location. Some older ones have it located a couple of inches to starboard. not a lot of room in the bilge. I was wondering if the high ventilation plate and intake location be a factor. Boats rigged with the Yamaha are rigged 1/2" above keel according to Yamaha and may not have a problem.

                      Mike BRP has been great and my local Evinrude dealer as well. They performed a run out of the prop shaft to eliminate the engine as the source of the vibration. All was to spec.

                      tjm

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                      • #12
                        IMO opinion, engine is too high.
                        Engine Sales and Service
                        Ph +1 954.463.1515
                        Fx +1
                        954.463.4904
                        Toll Free: 800.622.6747

                        oparker@parkeryacht.com
                        www.parkeryacht.com

                        Member of the MSHS Group

                        Comment


                        • #13
                          parker yacht

                          thanks, I appreciate your opinion


                          tjm

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                          • #14
                            Originally posted by Parker Yacht View Post
                            IMO opinion, engine is too high.
                            Surely looks that way.

                            Comment


                            • #15
                              Did the boat come from Robalo with the G2 installed? Or did a dealer install it? I thought Robalo equipped their boats with Yamaha power exclusively. Their website only shows Yamaha power as being available.

                              If a dealer installed the motor and selected the propeller then I don't see Robalo being involved in any way. But...

                              It is difficult when there a "quality of feel" issue. Much of the time noise, vibration, harshness is highly subjective. What is vibration to one won't necessarily be vibration to a different one. Performance expectations vary considerably. Which is why performance is all but never warranted.

                              There are several parties involved. Robalo (maybe), Evinrude, the Evinrude dealer and the customer. If a non-Evinrude propeller is installed that is one more party. The greater the number of parties involved the greater the number of fingers that can be pointed at others.

                              Good luck Mr. OP getting a solution to your problem. Please let us know what the cure(s) is/are.

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