Severe Cavitation

[BigN8]

This weekend my new to me 1997 Seadoo GTX was running fine then it slowly started cavitating to where you had to nurse it up on plane, then it just went completely to shit and the max speed you could achieve was about 6 mph. I was no where near shallow water so rocks were not an issue. When we got it back to the dock and on the jet ski dock we looked inside the nozzle and felt up inside the grate. Could not see anything really wrong.

I guess this means I need to rebuild the pump?? New wear ring and Solas impeller perhaps?

 

[Murf'n'surf]

Is the wear ring still in there?

 

[justason]

Anything pinched between the impeller and side wall? My first debris encounter was a stick stuck in there.....small and barely longer than the blades are thick. Hard to find/see

How many hours on it?

 

[Cobra Jet Steering LLC]

I had one of those once pretty good ski actually with the 787 engine. I had the bearings go out on the pump after water worked it's way in, however it made a lot of bearing noise out of the water when that happened.
Those pumps are very easy to pull off if needed, I agree with the very good possibility that something is lodged between the impeller blades.
You can always pull off the pump nose cone and inspect the condition of the gear lube plus those can be filled with the pump on the ski using the small inspection allen cap in the end cone.

 

[BigN8]

Thanks guys. I'm planning on pulling the ski out of the marina tomorrow or Wed and pulling the pump off

 

[robert843]

Usually cavitation is caused by something either bending or chiping the impeller I bet if you get it off you will see damage to it or something stuck in it

 

[BigN8]

Found the problem

 

[Murf'n'surf]

Tim to put it in the freezer!

 

[BigN8]

You think I need to replace that impeller @Murf'n'surf ?

 

[Murf'n'surf]

The impeller looks good to me from that pic.

 

[Cobra Jet Steering LLC]

Just replace the liner and clean up the leading edges of the impeller, also pull off the end cap and inspect the oil in the bearings I always used some S T P in the pumps because they don't use grease.

 

[BigN8]

After freezer I can just slide that wear ring out without disassembling the impeller correct? There really is no need to pull the impeller off right?

 

[Cobra Jet Steering LLC]

you can knock out the old one, I never put the pump in the freezer, to get the old liner out with the impeller in it I used a big screwdriver with the end heated up and bent in a 90 degree angle, used that to work around the end of the liner and tapped it out using the screwdriver and a hammer, it comes out pretty easily, the new liner goes in the freezer to make it shrink and easy to slip in the pump but the pump is at room temp .

 

[Murf'n'surf]

Sorry to blurt out random freezer comments and confuse the situation! As Jeff said, the new wear ring goes into the freezer.

 

[BigN8]

I did see a YouTube video where the guy put the whole assembly in the freezer for 4 hours. When he took it out he simply grabbed the wear ring and pulled it right out. It was pretty amazing.

 

[Ronnie]

I would have tried the freezer trick if I had known about it when I replaced wear rings in my seadoos. I ended up cutting out the old liner out with a reciprocating saw. Putting new wear rings in at room temperature was not bad, just used a rubber mallet on a piece of 2x4 to more evenly distribute the pressure. Check the outer circumference of the pump / wear ring assembly, I recall having a seadoo that had two holes drilled into the side which acording to my pwc mechanic were supposed to be filled with screws to keep the ring from rotating in the pump. I forgot to use these and never had a problem with the the ski but if you are a nut for details .... There are stainless steel wear ringS available but I don't know what their costs, pros and / or cons are .

 

[Cobra Jet Steering LLC]

the screws are in the 4 tec pumps not the 2 stroke pumps like he has, Actually he is better off removing the nose cone draining the very nice smelling oil from the pump bearings and placing the impeller shaft end in a vice then using a splined tool in the impellor to remove it, it makes everything a lot easier to do it that way but it can be worked out like I said using a specially modified screwdriver to tap it forward enough to grab on to it and pull it out using a couple of vice grips .

 

[BigN8]

Man that oil does stink! Wow!

 

[Cobra Jet Steering LLC]

really!! haaaa, if you did not have any water in the pump you will be fine in that aspect just fill it with gear lube a bit of marine grease and some stp , leave the vent cap off the cone when you reinstall it so it goes back on easily. the P T O on the rear of the engine has small splines where the drive shaft slides in. be sure that part is well greased also the driveshaft seal going from the boat to the pump needs a lot of grease if you neglect those two areas you will be having issues also if that ski has intermittent incidents with the engine shutting off for no reason and with no warning it is a common problem with that model it ends up being a bad ground from the battery to the engine , I solved my issue by running a second ground from on top of the engine to the neg side of the battery, the original one is by the starter so it corrodes easily from getting wet during use

 

[BigN8]

Well the freezer trick won't work. So now I have to remove the impeller and cut the wear ring.