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  1. #1

    15F/12F Jetpump Bearing Upgrade to 2012 Spec

    Kawasaki has come up with the ultimate jetpump bearing setup that could theoretically last twice longer than the previous design of 15F/12F. This new setup can be applied to all 15 previous model years (2004-2011) and all 12F as well (& possibly older 2-stroke 3-seater skis with 148 mm pump).

    Notice 2 bearings at the front of the impeller shaft.

    There are 2 main improvements on 2012 15F jetpump bearing setup as following:
    > 2 Front Bearings, doubling the load capacity of the previous single bearing setup resulting in longer lasting jetpump bearing life and less frequent maintenance. Also, there would be less vibration from the jet pump area since the impeller shaft is held tighter by the 2 front bearings (less radial movement).
    > Rear bearing is in the rear cone instead of the pump itself. This relocation has two benefits.
    1. Easy to check bearing condition and possible water intrusion just by removing the 3 screws from the rear of the ski.
    2. Since the distance between the front bearing and rear bearing is longer, the impeller shaft is held more stable resulting in longer life for the oil seals which job is to prevent water intrusion into the bearing area. This was implemented in 2011 model year (but 1 front bearing).

    What are the consequential damage(s) when jet pump bearing fails?
    > Impeller damage
    > Pump housing damage
    > Complete engine damage if you continue to ride with failed jet pump bearing (because ski will continue to run..). because the front pump bearing receives the complet axial thrust force (1550+ lbs) exerted by the impeller. If the bearing fails (disintegrates), the impeller/shaft would be pushing forwad on the drive shaft which in turn purshes on the crank PTO end. Crankshaft can't take such axial force and the crankshaft web would be grinding against the crankcase at the journal, shaving the metal away.

    What parts do you need in order to upgrade to 2012 setup?
    It depends what model year 15F/12F you have since there are several varieties.
    However, no matter what year you may have, you will need following parts:
    1. Jet Pump Housing P/N 59496-0074 (completely new part for 2012)
    2. Impeller Shaft P/N 13107-0739 (completely new part for 2012)
    3. Front Bearings P/N 92045-3744 x 2 (same as before, just need 1 more but replace your existing one anyway since it will be taken out)
    4. Rear Bearing P/N 92045-0112 (same as before on 2003-2006)
    5. Seals P/N 92049-3739 x 3 (same as before, but will be destroyed when taken out from your old pump)

    The new pump housing costs about $300. So, this upgrade is a good idea especially if your current pump is damaged by rock or worn out needing a replacement. If you just did your pump bearing job, wait till your next maintenance...

    There are some miscellaneous small rubber parts that can get easily damaged/deformed/lost. It would be wise to order and have them ready just in case since they are inexpensive. And they are:
    P/N 92055-025 O-ring (small)
    P/N 92055-3744 O-ring (med)
    P/N 92055-3741 O-ring (large)
    P/N 92093-3749 (seal)

  2. #2

    Join Date
    Aug 2007
    Great info!! I just serviced my pump this year.... new bearings, and seals. I'll definitely keep this in mid if the pump housing ever gets damaged.

    Just curious.. what's your take on the "wet" bearing pump mod. I believe it's just removing the bearing seals and filling the cavity with gear oil... right? Less friction? still safe protection?

  3. #3
    Grease vs. Oil

    Even SeaDoo couldn't make up their mind about "wet bearing pump". Some models they have, some other models don't have.

    Instead, I filled my pump bearing cavity with grease.

    Which one, grease or oil, is more likely to leak in case of seal failure?
    Which one is more likely to change in volume, expansion and contraction, when temperature changes?
    Which one is more likely to let water in?
    Which one is more likely to get mixed easily with water if/when water comes in?

    I would call mine, "Grease Bearing Pump Mod"

  4. #4

    Join Date
    Aug 2007
    Haha... good point. I did convert to the wet bearing mod... but will keep an eye out on how well it holds up. I'll probably go back to the standard grease method next time around. It felt wierd prying apart the seals on brand new pump bearings. Plus I dont think there's much noticeable performance difference.

  5. #5
    785xp's Avatar
    Join Date
    Feb 2006
    I had a 2004 STX-15F that I sold a few years ago and I still have the pump from it. I plan on buying another 15F very soon and was going to have this pump rebuilt. I have bearing #92045-3721, is this the same as the 92045-0112? Did I see somewhere that Impros can mod the old pumps so they don't cause damage to the engine when they let go?

    I had this happen on the 15F that I had so I want to make sure it doesn't happen again.

  6. #6
    1. Rear Bearing - Yes, I believe old P/N 92045-3721 is replaced by the new P/N 92045-0112 and they are the exact same spec bearing but just a different maker. If not, I will let you know.

    2. Impros Mod - That's for Ultras 250 & 260, not for 15F. Once you upgrade to the double bearing setup, you will be fine. Also, the bearing condition can be easily checked just by removing the rear cone and you can also easily repack the grease if need to.

  7. #7
    My name is Sean and I am addicted to STXs smokeysevin's Avatar
    Join Date
    May 2008
    Not that I am endorsing the wet pump mod but it did increase my rpms by 150-300 on my 12f. After a short ride it heated up enough to force the diff fluid out past the seals resulting in a huge cloud of horrible smelling steam/smoke following my ski, the oil forced out let water in and I had to clean the pump out and dry it up and replace it with grease. Just my experience.


  8. #8

    Join Date
    Aug 2007
    hmm.. good to know. I'll keep an eye on mine.

    Im a bit suprised though... I wouldnt have thought the oil inside would get that hot, considering cool water should be running throught the jet constantly, and the only thing to lubricate are the ball bearings. Did you have it very packed? or leave some space for the oil to expand?

  9. #9
    Quote Originally Posted by joemama422 View Post
    Did you have it very packed? or leave some space for the oil to expand?
    It doesn't matter.

    Oil expands and it takes up air space.
    And air is trying to expand as well.
    The bearing area is air/water tight - until the seal blows.

  10. #10

    Join Date
    Aug 2007
    Gotcha... I know air can expand, but it can be compressed... most likely by the oil... but that still creates a condition for the seal to blow.

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