I just bought my first seadoo jet boat, a 1996 challenger 787 single engine. Upon first ride the boat would not plane out hittinh 7000rpms, so after reading alot i pulled the pump and replaced wear ring and impellor with a skat trac 17/22 pitch. Anyhow put it in went my self and felt way better, then went grabbed my son and wife and in felt the same as prior to the repair. I di dnot use the pump to hull seal but rather used alot of rtv black as recommended by my dealer. there are no leaks in the hull but still cavitates badly, once on plane runs very well tack is about 6600rpm. Any other ideas??
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PLEASE HELP!! Challenger cavitates
- Thread starter jamiegaga
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Dr Honda
Well-Known Member
First... your dealer is an idiot. Now it will be hard to get the pump back off since it's glued on. (which you need to do)
Your problem is your carbon seal on the driveshaft. You will need a new carbon ring, stainless ring, the O-rings for the stainless ring, a new C-clip, and a couple zip-ties.
Pull the pump, and the driveshaft... swap the seal and related parts, and reinstall.
Your problem is your carbon seal on the driveshaft. You will need a new carbon ring, stainless ring, the O-rings for the stainless ring, a new C-clip, and a couple zip-ties.
Pull the pump, and the driveshaft... swap the seal and related parts, and reinstall.
well i mentioned the carbon ring and he laughed and said the boat would sink if that was bad?? Anyhow so I cancelled the order for the driveshaft repair kit (seals,carbon ring and so on) and the pump gasket as he stated it is not needed! So i have to pull the driveshaft out???
1 more question, when i remoced my pump there was only one hose with a clamp on it and just the 1 fitting on th eback of the pump for it, this allows water to spray out the back when running. ( i have read where there are supposed to be 3 in total? have not seen the other 2)
phough5757
New Member
Boat Pumps
Boats only have One hose on the pump. It goes to the High pressure side of the
Pump. It supplies water to the Cooling system. Skis use three. Two are for
the self Bailers, they go to the low pressure side of the pump to make a
vacuum. To drain the Hull.
Boats only have One hose on the pump. It goes to the High pressure side of the
Pump. It supplies water to the Cooling system. Skis use three. Two are for
the self Bailers, they go to the low pressure side of the pump to make a
vacuum. To drain the Hull.
Thank you for clarifying that, I have pulled the pump now and will re seal it with the proper seal and not rtv this time, but now how do i correct the carbon ring problem to hopefully solve this cavitation problem.
phough5757
New Member
Carbon Seals.
Did the drive shaft stay with the Pump? If not - in the engine compartment
compress the black bellows. I left the hose clamps on. While holding the
bellows with one hand, twist and slide the stainless collar towards the bellows.
When the collar has moved exposing either a rubber O-ring or a metal C-clip.
Slide whatever one You find forward to the rubber PTO boot.
Remove the Clamp from the PTO boot ( the small one on the driveshaft ).
I put a shop rag under the PTO and collar to catch it when You slide the
Driveshaft out the rear. The most common problem is the bellows looses its
ability to press against the stainless collar. Putting it back together is harder
with a new bellows. Check inside the collar for the two O-rings and the
carbon seal for any abnormal wear. I replaced everything. My boat had some
Driveshaft protectors (plastic sleeve) that had broke and parts of it came thru
my bellows. Better to remove it if you still have it or them on Your boat.
Good luck and I hope this helps.
Did the drive shaft stay with the Pump? If not - in the engine compartment
compress the black bellows. I left the hose clamps on. While holding the
bellows with one hand, twist and slide the stainless collar towards the bellows.
When the collar has moved exposing either a rubber O-ring or a metal C-clip.
Slide whatever one You find forward to the rubber PTO boot.
Remove the Clamp from the PTO boot ( the small one on the driveshaft ).
I put a shop rag under the PTO and collar to catch it when You slide the
Driveshaft out the rear. The most common problem is the bellows looses its
ability to press against the stainless collar. Putting it back together is harder
with a new bellows. Check inside the collar for the two O-rings and the
carbon seal for any abnormal wear. I replaced everything. My boat had some
Driveshaft protectors (plastic sleeve) that had broke and parts of it came thru
my bellows. Better to remove it if you still have it or them on Your boat.
Good luck and I hope this helps.
Thank you for the description, I appreciate it. I now have the boot loose and all but cannot get the collar to move towards back of the boat to access the seal to remove it. I tried prying but there is no where to pry against. Is it seized possibly? my bellows are very hard and tough to compress. Any ideas?
If the pump is out, the driveshaft should wiggle out of the splines and slide right thru the seal carrier tube - did you remove the pump from the rear of the boat already? Have a helper hold the driveshaft to the inside of the boat while you push the steel collar rearward and pull off the clip - this lets the shaft out thru the middle, this helper will be needed after you get your pump ready to go back in, it is a little harder the first time - ya know the story about riding a bike.
Thank you again!!! I got it out! Is it possible to reuse the neoprene seal that was just installed 3 days ago or should I change it again when re-installing the pump? My carbon seal didn't "look" all that bad but the water pouring in would have sunk the boat. Any tricks to reinstalling or install like everything came out and hope for a perfect seal between carbon seal and carrier. I ordered the (sbt driveshaft repair kit) 3 seals, carrier, carbon seal, and new drive shaft boot. Am I forgetting something
phough5757
New Member
I think thats everything.
Make sure You have the rubber bumpers at either end of the driveshaft.
Reinstall the driveshaft but leave the seal loose until You have the Pump in.
I used a piece of 2x4 about 4 or 5 inches long and lay it under the shaft,
against the Motor(PTO) for something to pry on. Make sure You don't bend the
Stainless seal ring. I also put a dab of grease inside the stainless ring to
lube the o-rings.
I have never reused a neoprene seal. When I go to the seadoo shop I buy a
handfull of stuff like seals and gaskets incase I screw one up.
I had problems getting the rubber bumpers to stay in the ends of the driveshaft
because someone told Me to use a dab of grease to keep them on or ease in
the installation. I would push them in and they would come back out. I tryed
twisting them and they came back out. Air pressure behind them kept pushing
them out. I have access to a hypodermic so I removed the air and it was hard
to pull the bumpers out.
With the pump in and the seals not installed You should have about 1/8" inch
of movement in the driveshaft. I put the driveshaft in the pump end to make
sure the seal at the pump was good and tight and the transition between
shaft and pump was smooth. I then go inside the boat and clamped the
bellows and carbon seal to the Hull. Don't forget the "PTO - Driveshaft" seal
or boot, what ever You call it. The factory uses Otiker? clamps and I have
never got the knack of them. I can't get them to close the clamp.
I just use wire ties. I put the one on the PTO first and pump some grease
thur the grease fitting till it comes out by the shaft then wire tie it.
I hope this helps and good luck!
Make sure You have the rubber bumpers at either end of the driveshaft.
Reinstall the driveshaft but leave the seal loose until You have the Pump in.
I used a piece of 2x4 about 4 or 5 inches long and lay it under the shaft,
against the Motor(PTO) for something to pry on. Make sure You don't bend the
Stainless seal ring. I also put a dab of grease inside the stainless ring to
lube the o-rings.
I have never reused a neoprene seal. When I go to the seadoo shop I buy a
handfull of stuff like seals and gaskets incase I screw one up.
I had problems getting the rubber bumpers to stay in the ends of the driveshaft
because someone told Me to use a dab of grease to keep them on or ease in
the installation. I would push them in and they would come back out. I tryed
twisting them and they came back out. Air pressure behind them kept pushing
them out. I have access to a hypodermic so I removed the air and it was hard
to pull the bumpers out.
With the pump in and the seals not installed You should have about 1/8" inch
of movement in the driveshaft. I put the driveshaft in the pump end to make
sure the seal at the pump was good and tight and the transition between
shaft and pump was smooth. I then go inside the boat and clamped the
bellows and carbon seal to the Hull. Don't forget the "PTO - Driveshaft" seal
or boot, what ever You call it. The factory uses Otiker? clamps and I have
never got the knack of them. I can't get them to close the clamp.
I just use wire ties. I put the one on the PTO first and pump some grease
thur the grease fitting till it comes out by the shaft then wire tie it.
I hope this helps and good luck!
phough5757
New Member
Yes
I believe so. Is it tight?
Go dump it in the lake and see if it leaks.
Good luck and have fun!
I believe so. Is it tight?
Go dump it in the lake and see if it leaks.
Good luck and have fun!
ok, i am slowly giving up on this thing, lol! I have changednow impeller skat trak 17/22, sbt wear ring, sbt carbon seal and retainer, new driveshaft bumpers and neoprene seal for pump to hull. It still cavitates intermittenly, when it does it will not get on plane at all just revs to 7000rpm and exhaust smokes like crazy. it always does it with 2 adults and 1 child and sometimes with myself and 1 child. the other day it launched fine and after playing around a bit it began cavitating so bad i had to hammer the throttle and slowly walk to the front of the boat to help it plane out. then cruised for 3 min stopped tried again and she planed in 4sec. tried 3 times perfect everytime, 4th time cavitated liek crazy. sorry for the long post guys but i am confused. Please help!!!
phough5757
New Member
How much space?
This may be to late. Did You check the clearance between the impeller and the wearing ring? Seadoo manual says .007"-.017" = New and .040" = Max.
You said a new impeller was used or an aftermarket. Was it used or new?
Good luck and PM Me if You like.
Patrick.
This may be to late. Did You check the clearance between the impeller and the wearing ring? Seadoo manual says .007"-.017" = New and .040" = Max.
You said a new impeller was used or an aftermarket. Was it used or new?
Good luck and PM Me if You like.
Patrick.
1fast04neon
New Member
im having the same problem on my 97 single engine..i havent pulled it apart yet but the exact same thing is happening.. keep me posted on what u find out..thanks
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