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  1. #1

    96 SeaDoo Challenger cavitation issues

    I have a 96 Seadoo Challenger that is suffering intermittent cavitation. Some times it launches out of the hole fine, some times it cavitates really badly. I replaced the impeller with a Skat-Trak 14.5/22.5 and new wear ring and the problem continues. Could some one help me with a quick list of possible causes. I don't see any water coming in from the stock carbon ring. That would seem to me like the next obvious place to look at...but I have heard if I don't see any water leaking in I shouldn't worry about it? Anyone have thoughts on this? Do I need to use more silicone when I seal my pump? Can a poorly sealed ride plate cause cavitation?

    Thanks in advance.

  2. #2
    How about the rubber spinner attached to the front of the impeller? Mine must have gotten chewed off the last time I sucked up the tow rope.

  3. #3
    mark2m's Avatar
    Join Date
    Mar 2008
    Greenwood Lake, NY
    That rubber nose boot can and will cause it if it is damage enough to cause a turbulent water flow. Also while you may not be seeing water entering through the carbon rings a problem with the carbon ring setup that on hard acceleration it will suck air from the bilge causing cavitation. If you have the driveshafts with the three grooves on it you can try and increase pressure on the accordion setup by moving the mating surface closer together. That or replace the whole carbon ring assy with the older setup that consist of a greased bearing in a housing which many have gone to. You can search for retro carrier here or on for more info and write-ups. I removed my carbon ring setup for the carrier and it is a world of difference.

  4. #4

    Ride Plate

    could be it too. Many times the sealing of the plate to the boat will fail,
    causing cavitation. As mentioned before, the carbon ring/pump engine alignment can be an issue. Check motor mounts too. Good Luck!

  5. #5
    ok thanks for the input. I pulled the drive shaft today to inspect the carbon ring assembly. I found the carbon ring gouged up. I used a piece of 1200 grit sand paper and re-surfaced the carbon ring on a piece of flat steel. Did the same with the stainless steel ring. Cleaned it all up, looks much better now. Installing a new rubber nose boot on the impeller, another new wear ring as well as new rubber bumpers front and rear on the drive shaft. I will check engine to drive shaft alignment when it all goes together.

    NEW QUESTION: How do I get the darn ride plate off the bottom of this boat? I want to take it off so I can re-seal it. I pulled the six ride plate mounting screws from the bottom of the boat. I used two 2x4's placed inside the pump housing and a jack to press out the ride plate. So far its a no go with a 6 ton jack. Do I need more jacking pressure or did I miss some screws?

  6. #6
    mark2m's Avatar
    Join Date
    Mar 2008
    Greenwood Lake, NY
    Sounds like you are getting it under control. I've have not pulled the pump shoes off my boat but I believe that their are only 6 six attaching it to the hull like you said. The jack and 2x4 is the way I've heard it done. You may want to try and take a razor blade around the outside of the shoe and cut any of the sealant before you try applying pressure again.

  7. #7
    Sounds like you have a stubborn one. Put as much pressure on it as you dare with the bottle jack and as already suggested cut as much silicone away as you can without gouging your hull. When I took mine off I also used a guitar string as a saw to cut through the silicone from the back to the front until she started to give. Good luck.

  8. #8
    1996 Sea Doo Challenger (787x1)
    Join Date
    Aug 2007
    My vote goes to the carbon ring, due to the cavitation being intermittent.

  9. #9
    Got the pump shoe off the boat last night. The trick was using heat!

    Here is the trick to removing the pump shoe from a SeaDoo challenger.

    Picked up a Douglas Fir 4x4 from home depot and cut it to about 4 foot in length. $12 I was breaking the 2x4's I had.

    Picked up a shortie 20 ton floor jack from Harbor Freight for $38.

    Remove jet pump and drive shaft from boat.

    Remove the six mounting screws from the bottom of the pump shoe.

    place a heat gun underneath the boat pointing the heat at the bottom of the pump shoe. You want to get the aluminum shoe throughly warm probably around 150 to 200 deg.

    While it is heating up prepare your jacking setup.

    place the 4' long 4x4 inside the pump housing/tunnel. Push it all the way in.

    set your jack on top of the 4x4 underneath the rear fiberglass step of the boat. I used a piece of 1" x 6" X 12" thick piece of scrap aluminum to protect the bottom of the rear step of the boat. You could also use a 2x4.

    use a jack stand to support the other side of the 4x4.

    start jacking. The pump shoe should be just about too hot to touch. Keep the heat going from the heat gun. It should only take about 20 min to heat it up.

    Start applying more pressure to the ride shoe. The 4x4 should be placing most of its pressure to the inside of the ring. Do not let the 4x4 place jacking pressure on the rear trim plate of the pump shoe or you will break it off. You may need to re-position your jack stand and jack to keep this from happening.

    Apply pump pressure and keep the heat going. You will see the pump shoe start to pull away. Once that begins to happen its all down hill.

    Use a wire wheel on a die grinder to help remove the silicone. You can also try using a good pressure washer.

    I will try to attach a photo of the setup a little later.

    Thanks for all of the help so far.


  10. #10
    Here is a interesting link for single engine seadoo jet boats.

    It has a lot of neat information in it. Here is a little snip from it:

    Pump Shoe - The pump shoe is the actual metal part (bolted to the hull) that the pump body seals up against. In the case of the 14.5's, the shoe and the ride plate are made as one piece. It is "fundamental" that this shoe/ride plate is perfectly sealed to the hull with a high-grade silicone sealer. Herein lies a lot of the cavitation problems experienced by many 14.5 owners. Many of these shoes came from the factory with breeches in the silicone that sealed them to the hull. On these units, no kind of custom prop, etc, can eliminate the cavitation. The pump shoe/ride plate "must" be removed and resealed using "Permitex 66c Industrial Clear Silicone" (available in auto parts stores). Removal of the pump shoe is difficult (usually done with a hydraulic jack between the plate and the rear swim step). Once off, all surfaces must be completely cleaned of the old sealer. It is impossible to over emphasize the absolute importance of have this area attended to. We recommend This procedure for "every" single motor 14.5.

    As added insurance to sealing between the pump shoe and pump case, we recommend a foam pump sealing-ring (available from the SD dealer). This inexpensive foam ring assures that there are no unknown gaps in the crucial sealing surface between the pump case and the pump shoe.

    Wear Ring - The wear ring is a removable Teflon plastic liner that the impeller spins within. In a perfect world, this ring has no grooves or gouges on its surface, and it fits closely to the impeller’s outside diameter. However there can be considerable cavitation if the wear ring is gouged or grooved (as can happen from digestion of rocks or branches). In addition to the cavitation, a damaged wear ring reduces pump efficiency in a way that can cause the engine to run a few 100 rpm higher than normal (for any given speed). The end result is reduced pump thrust, and reduced fuel range. If your wear ring is damaged in anyway, it’s cost effective to replace it...and then stay away from rocks.

    Drive shaft protector - The 14.5's come from the factory with a white plastic sheath that slips over the drive shaft. This free spinning sheath is intended to make it easier to remove ropes that might get wrapped around the drive shaft. Unfortunately, the forces of debris entering the pump often causes this protector to fracture and break apart, thus contributing to cavitation. We chose to cut this protector off at the front of the drive shaft (a small part of it must remain to seal the shaft), thus increasing the pump’s water intake area. At this same time we shortened our dock-lines to a length that would bake it impossible for them the wrap the drive shaft when tied to the cleats on the top deck.

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