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  • Seal Damage Prevention

    My elderly ****en Retriever woke me up to get an early morning walk, couldn’t go back to sleep. So, probably did too much thinking, again, but…

    There have been some recent threads regarding crankshaft Speedi Sleeves, mid shaft bushings, and lower unit removal and installation, and others where a little extra effort can prevent damage to seals.
    Common sense would dictate seal damage prevention. I thought I would pass along some precautions I take while working around seals.
    First off, immediately when I remove my lower unit, I wrap tape around the drive shaft splines to protect same. The edges of these splines are sharp. Say you’re replacing the upper lower unit driveshaft seals. Sharp edges of the splines can slice a cut in the seals while placing them over the driveshaft. Granted these seals are somewhat larger diameter than the splines, but if you are careless, you can damage them. So why not take five seconds and put tape around the splines.
    What about when reinstalling your lower unit? Of course, you can’t leave the tape on, and I know you all put a bit grease on the splines. I put a fine film of grease over the entire shaft, including seal and mid-shaft bushing mating surfaces. But have you ever had to struggle to line up the driveshaft and shift shaft into their mates? What if while you’re struggling you have the shaft at such an angle to the seals that the splines cut into your driveshaft seals in the oil pump? You must take your time ease the shafts into their mates.
    In four stroke oil pumps, there are two seals for the driveshaft. Besides protecting the crankshaft before the crankcase seal, are these seals extra protection to keep contaminates from damaging the first oil pump seal? Could the contaminates promote the seal wear and its mating crankshaft, thus requiring a Speedi-Sleeve repair?
    Remember that mid-section bushing, some have said that you can just remove it and don’t bother to replace it. The published purpose of this bushing is to prevent excessive shaft wobble. However, a result of not having the bushing in place, IMO, could be while installing a lower unit the allowance for increased angle could cause seal damage.
    Chuck,
    1997 Mako 191 w/2001 Yamaha SX150 TXRZ Pushing Her

  • #2
    Thinking about it, the splines are going into the crankshaft before the seal is up against the drive-shaft.

    Yes, you could nick the oil seal doing the install BUT, the splines are greased, hopefully your going slow (mid-section bushing help align as well as another set of hands).

    Short of the last couple weeks chatting about sleeves, etc, the sleeve, leaks have not been an issue.

    Remember too, the seal isn't that delicate. Unless you ram the driveshaft hard and fast up the mid section, damaging the seal shouldn't be an issue.

    I'd think regular maintenance, oil changes, etc, is probably the best thing you can do to avoid premature wear.

    Similar seals have been used on engine crankshafts (automotive, etc) for decades. Also, the crank is WAY HARDER than the seal is should you develop a leak.

    I'd be be curious, percentage wise, (by Rodbolt), for all the crank leaks he's had to do, that the "sleeve kit" was even needed..
    Scott
    1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR

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    • #3
      I've never noticed any burrs or special wear on my upper driveshaft splines but it is worth checking and remove any with some Emory cloth before replacing shaft....some motors may be more subject to warn splines with burrs than others???

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      • #4
        Those drive shafts are super hardened...

        The leaky crankshaft seals has just come up recently with one known engine(the F150 with the balancer that destroyed itself).

        For the years on this forum, I don't remember any other (or VERY FEW) issues.
        Way more issues with carbs, VST's, etc.

        The leaky crankshaft seal is VERY RARE and a non issue IMO...
        Scott
        1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR

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        • #5
          Originally posted by TownsendsFJR1300 View Post
          Those drive shafts are super hardened...

          The leaky crankshaft seals has just come up recently with one known engine(the F150 with the balancer that destroyed itself).

          For the years on this forum, I don't remember any other (or VERY FEW) issues.
          Way more issues with carbs, VST's, etc.

          The leaky crankshaft seal is VERY RARE and a non issue IMO...
          A quick search found four oil pump seal leak threads within the last couple of years.

          I wonder why Yamaha issued a service bulletin, offers the "sleeve kit", and why they have reengineered the crank to have a hardened replaceable collar?

          I would say not so common rather than very rare. Rodbolt has done quite a few, so he says in this quote.

          Originally posted by rodbolt17 View Post
          I have done many sleeves, some 3 or 4 times.
          typically we see 600-800 hours between sleeve replacements.
          I use locktite 518 on the sleeve ID to prevent leakage between the shaft and the sleeve.
          no mystery in the pump itself only issue we ever have with sealing the pump is getting the screws out.
          I would think most of us weekend warriors would never have this problem, or recognize it they did. If someone finds oil on their driveshaft while doing service to their lower unit I would suspect the lower crankshaft seal within the oil pump housing. Being cognizant of this issue, I would think it prudent, if for some reason the powerhead has been pulled, to pull the oil pump and inspect the crank for grooves.

          As far as those screws Rodbolt mentions, I can see why they're nearly impossible to remove to replace seals within the oil pump housing, thus the recommendation to replace the pump that already has the seals installed rather than attempting to replace the seals in the existing housing.

          [IMG]F225.OilPump.Screws by Charles Postis, on Flickr[/IMG]
          Chuck,
          1997 Mako 191 w/2001 Yamaha SX150 TXRZ Pushing Her

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          • #6
            yep, stuff in salt water tends to be a problem

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            • #7
              shafts wear.
              it is a simple fact of life.
              I have sleeved more harmonic balancers surfaces than I care to remember back in the automotive days.
              I sleeve input shaft surfaces on Volvo and mercruisers all the time.
              if all that is wrong with the shaft assy is a grooved surface why should I spend 480 dollars of my customers money when the sleeve is about 70 bucks?

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              • #8
                I'm not saying they don't wear.

                Having a repair kit is also a major plus.

                RB works on more Yamaha engines in a day or two than I have in my entire life (and likely most of us).
                So yes, I expect him to see a WHOLE lot more, etc. (3 decades of wrenching, there's not much he hasn't seen)

                All I'm saying, with the thousands of folks that post here (specifically about crankshaft seal failure) looking for help, it's not a common problem.

                *There's not much you can do about it UNTIL / IF you get a leak anyway. It's nice to
                know there is a fix, but it's not something I'd concern myself about till then (short of keeping up maintenance, flushing, etc).

                Four threads in a couple of years, not much but ok. There's that many threads a WEEK re say ethanol damage.

                Balancers, VST's, fuel pumps, multi-carb set up/cleaning, ETHANOL is WAY more the common issues.
                Scott
                1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR

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