I have been getting cavitation during take off with my 96 GTX, I will rev to about 6k and not accelerate untill I get above plane. I read it maybe the wear ring but I measured it and the clearance is less then the 1.0mm the book says. I also read that it maybe a sealant ring between the pump and the housing. But the part diagram shows no gasket there. So I am not sure what I need to do.
1996 GTX take off cavitation
- Thread starter Raksj04
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Ckrawiec
Well-Known Member
Take a look at the attachments as a guide....
Thank you. I remember the leading edge of one of the blades has a nick in it. I want to replace it, but I don't have the funds right now to replace it correctly, new impeller, pump rebuild kit, and wear ring. Thats pushing $400. I think I will try to smooth out that nick best I can.
Ckrawiec
Well-Known Member
Also, make note of the last item in the troubleshooting attachment : Peak performance is delayed until higher RPM range is reached (fits your OP description).....RAVE valve stuck open [POTENTIALLY]....I'd check/eliminate that before I tried messing with the impeller...just sayin.....
It's free to pull your pump and inspect the components.
A nick on the impeller will not cause your issues.
The neoprene seal is not shown on the diagram but a good addition to your ski.
Post some pictures of your impeller and wear ring.
If you are reaching 6,000 rpm and not moving the issue is in the drive system not the engine.
A nick on the impeller will not cause your issues.
The neoprene seal is not shown on the diagram but a good addition to your ski.
Post some pictures of your impeller and wear ring.
If you are reaching 6,000 rpm and not moving the issue is in the drive system not the engine.
JeremyD615
Well-Known Member
Did you check the wear ring from the intake side, or just the nozzle side? I’ve seen some that look decent from the back, but are torn up on the inside...
I clearly hear/feel cavitation, like someone is holding the clutch in or a slipping trans, it revs up and doesn't go anywhere. It doesn't bog down or anything.
If that make sense. I know that this is a direct drive system, lol, but that was the best way to describe it.
From the front, i had the pump removed. I had the steering cable brake while out on the lake. Luckily it would turn in reverse.
I will.
It has had this issue for awhile. It was a family thing that I finally got the ability to work on.
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LikeabossTM
Active Member
A little chippy on that one edge but I don't see anything that screams cavitation from that impeller, or wear ring, and the gap looks fine.
I ordered a neoprene ring. The carbon seal was just replaced. Honestly I think it is the neoprene seal. The pump seems to no have no gasket or seal of any kind between the pump and housing, just plastic on plastic.
I think you are on the correct path now. No seal will suck a lot of air there.
I will post results once the part comes in. I order one for a 96 XP, which has the same pump part number. I am not sure if the seal is part of the wear ring for the GTX or what.
UPDATE: So I have her in the water for about a week straight and was able to test a few ideas.
I believe the carbon seal is the source of the issue. I don't think I have enough press on the carbon seal to fully seal. After removing and installing the jet pump many times, including removing the engine to replace the cylinder gasket and some piston rings that broke while I was putting her back together. I didn't grease the shalf and install the new grease seal.
I put a couple pumps of gease in to the z fitting and the shaft moved back a couple inches. And I was able to improve take off for a couple of "launches".I also noticed splashing inside the engine compartment that looked like it came from the ring.
So I need to pull the pump again, getting pretty good at it, and install the grease seal.
I believe the carbon seal is the source of the issue. I don't think I have enough press on the carbon seal to fully seal. After removing and installing the jet pump many times, including removing the engine to replace the cylinder gasket and some piston rings that broke while I was putting her back together. I didn't grease the shalf and install the new grease seal.
I put a couple pumps of gease in to the z fitting and the shaft moved back a couple inches. And I was able to improve take off for a couple of "launches".I also noticed splashing inside the engine compartment that looked like it came from the ring.
So I need to pull the pump again, getting pretty good at it, and install the grease seal.
cocacola
Member
this was what was making mine do this...
GGuillot
Well-Known Member
I chased this issue on my 97' GTX for awhile, new carbon ring/hat, more pressure, nothing was working to eliminate the cavitation and a little water showing up in this area.
Ended up being a bemt drive shaft between the pto and carbon seal area. Noticed the bellow wobble revving on the hose.
Ended up being a bemt drive shaft between the pto and carbon seal area. Noticed the bellow wobble revving on the hose.
Bent drive shaft? Damn i hope not. I hope it is just me skipping steps. Since I able to fix it with a little grease. But I keep it in mind.
AKnarrowback
Well-Known Member
I chased a air problem on my 97 gtx for a long time and corrected it by resealing the pump intake (ride shoe) to the hull, part number 34 in the picture. It is made of plastic and after removing all the parts that hold it in place it fell out of the machine without prying, the sealant had seperated from the plastic. When all other simple options are exhausted consider resealing the pump area assemblies that bolt/seal to the hull (parts 18, 34, 47). It takes a little time, is not complicated, and it might be the solution.
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There is a rubber bumper on the impeller side. It may not have move inches, didnt measure but I could see it move. Maybe a 1/4 to 1/2 inch.
Is there supposed to be a bumper on the PTO side?
What sealant did you use.
I feel by the time next summer rolls around this PWC will have 50% new parts. Lol
I just checked the diagram, well I will be damned i have seen that diagram a couple times and never noticed the bumper on both side.
I also have a clip for part #7 instead of an o-ring. Came with the carbon ring kit.
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AKnarrowback
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