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F150 tapping

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  • F150 tapping

    Guys, My F150 is a 2004, with 600 hours. New ( latest version ) balancer installed spring of 2016. Maybe 50 hours on the new balancer which is already starting to
    'whine' a little. Question : can any one identify the 'tapping' that is heard when picked up off idle in the attached video ? It seems to be coming from the balancer
    area, but sounds too 'tinny' to be some of the reciprocating shafts in that piece ?

    Thanks, JB
    '87 Outrage 18, '04 F150
    '97 SeaArk 15, F25

  • #2
    Bumping this hoping Rodbolt will have a look. Sounds like parts are rattling in motor....

    I posted on another forum for Ole Parker and Andy Sim to weigh in.
    Last edited by pstephens46; 07-09-2018, 08:03 PM.


    • #3
      Forwarding one MT opinion. At any rate, OP knows it has to come off and be inspected.


      • #4
        Thanks Pat ,

        The new balancer is the current part # , so it’s the latest
        one. No erosion of teeth on the old balancer was seen. The only issue I noticed was that the teeth ‘bound’ slightly when the shafts were rotated. Andy at SIM has seen my video and did not recognize the tapping - he commented that the balancer ‘whine’ did not sound abnormal. He recommended
        pulling it for inspection. The new balancer came from SIM.
        Plan to pull it next weekend for a look.

        '87 Outrage 18, '04 F150
        '97 SeaArk 15, F25


        • #5
          I think the whine is more apparent when revving the motor. One thing for sure, it will get louder if it is the balancer. The tapping bothers me more.


          • #6

            Per your e-mail, I looked closer to my old type 3 balancer that was whining (and replaced).

            Below is a close up pic of the composite gear that fails. I did not see any other fatigue, no noticeable gear slop either.

            I did notice that (where the screw driver is pointing), the gear pattern (that touches the steel gear), is ONLY about 1/3 of the tooth.
            That shiny liquid is left over oil which the gear picked up. The wear is also noticeable without the oil, about impossible to see in the picture.

            Short of ^^, the gears seem to mesh very tightly, no binding what so ever...

            There's really nothing inside the balancer to "tap".


            • #7
              Thanks Scott,

              I'm with you ...... don't see what, if anything, within the balancer itself could make that tapping that sort of comes and goes. Looking at a horizontal section of the engine, looks like the crank counterweights
              pass very close the balance shaft cap bolts. But assuming one of these had somehow backed out enough to hit the crank - I'm sure the noise would be major. Other remote possibility ; one of the balancer shaft bearings ( roller / ball ? ) is failing and the tapping is a roller rattling inside the race ? Anyway I'm going to pull it tomorrow. Once off, if nothing reveals itself - thought I would remove the plugs and spin the engine to see if the noise is evident without the balancer. Is there any reason NOT to spin over the engine without the balancer on it ?

              I'll let you know what I find.

              Best, JB
              '87 Outrage 18, '04 F150
              '97 SeaArk 15, F25


              • #8
                Pat has ran his with the actual balancers out, just the cover installed. Vibrated a bit more, but no damage..

                I don't believe he plugged any oil holes (which may be a good idea as there's nothing inside to restrict oil pressure)..


                • #9
                  Update : I pulled the balancer for a close inspection. Everything looked and felt perfect : no gear tooth erosion, shafts spin freely with no bearing noise or any kind of binding.
                  Looked very closely, with a bright light, at all of the engine bottom end components - all looked perfect with no sign of any metal on metal contact. No metal shavings of any
                  kind on any surface I could reach.

                  The ONLY thing I noticed, and have a call in to Sim Yamaha about this, is a small amount of 'lash' between the gears which drive balancer shaft #2 off of shaft #1 that mates to the
                  crankshaft gear. I didn't have a dial indicator and could not measure this ........ doesn't really seem excessive but it's there.

                  So after re-assembly and starting the engine ...... the tapping is gone !

                  '87 Outrage 18, '04 F150
                  '97 SeaArk 15, F25


                  • #10
                    I would think they'd be a knats hair of play, especially as the engine warms up, tolerances tighten up.

                    There is no way to adjust the gear lash anyway, un-less the unit /(gears) are worn out.

                    Glad to hear it's quiet again, enjoy!