'92 XP cavitation problem.

[aphexandy]

I just bought a pair of Seadoo Xp's. one is a '91 that runs great, the other is a '92 that didn't run when I bought it. I search and found the problem to be a the stator. With the new stator installed, I fired it up, and it ran, but wouldn't rev past 5500. I tore down the carbs, and found that the fuel control needle valve spring was out of place. I fixed that , and now it will rev to about 6000. I still need to find out why i cant get more RPM out of it, but a bigger problem then that is that any time the boat hits a wave it cavitates horribly. it has a new scoop grate, (same as the '91) the only difference between the 2 are 92 has a pipe, 91 has a skat-trak 720v impeller. and of coarse one is a 580 yellow, other is a white. any help with the cavitation or RPM issues i'm having would be greatly appreciated.

[aphexandy]

Re: '92 XP cavitation problem.

anyone have a suggestion on my problems? I have checked to see if the shoe is leaking, and it does have a VERY slow drip on the left side about half way back, but could this be my problem? how do I check to see if the thru-hull seal is leaking? anything else I should check for? thanks guy's.

[joyenter]

Re: '92 XP cavitation problem.

Measure clearance between impeller and wear ring.

[aphexandy]

Re: '92 XP cavitation problem.

I have looked at it, and it seems good, tighter then y 91, but I havn't busted out the feeler gauges yet. my claymer book says .40 inch is the wear limit, but it desn't say weather there should be a difference between leading edge clearance and center of the blade? anyone know about this? it appears the the leading and trailing edges are tighter the n the center of each blade is that normal?

[fpresty]

Re: '92 XP cavitation problem.

From experience, I do not think so.

[aphexandy]

Re: '92 XP cavitation problem.

I had it out again today, and I am stumped. watching a friend ride it in lake Michigan with a little chop, you can see that the grate is stil completely submerged, yet it cavitates everytime the bow hits a wave and slows down the boat. I did get out the feeler gauges, and the gap looks like about .15" so I don't think its the wear ring. Still searching for help.

[joyenter]

Re: '92 XP cavitation problem.

Are you sure the drivesharft is not slipping??

[aphexandy]

Re: '92 XP cavitation problem.

I hadnt even though of that, how do I check to see if it is? I though the driveshaft was splinde into the impeller? is there sopposed to be some play in the shaft? thanks for the help guys.

[Bill O'Neal2]

Re: '92 XP cavitation problem.

The most common things are that the sealant is missing between the pump and the pump support plate. That is easy enough to fix with a nice fat bead of Ultra Black around the support plate/werar ring mating surface, then reinstalling the pump so it beds into the sealant. Let dry 24 hours before riding. Next most common is a bent impellor.

[aphexandy]

Re: '92 XP cavitation problem.

Bill O'Neal2; I've seen your posts on here, and you seem to know your stuff. I've been waiting to hear your oppinion. I'll tear it apart and take a look. now I have a new question, if the impeller is bent, what would be a good all around performance replacement. I do all sorts of riding from cruising around in-land lakes to rivers, to jumping waves out in lake MI. my '91 has a Skat-Trak "720v" but I can't find any info about it (pitch etc.) and it seems to run good. Thanks again guys keep the help coming.

[surveyguy]

Re: '92 XP cavitation problem.

you're trying to get how much more rpm's ? My '95 750 goes to 6200. Cavitation would make it rev higher. If it were only going 6000 I wouldn't be looking at cavitation issues.

[Bill O'Neal2]

Re: '92 XP cavitation problem.

I have never seen or heard of a Skat Trak 720V impellor. Are you sure that is what you have in there?

For information try www.impros.com ( Dave is currently on vacation for a few days, I think )

[xdrian]

Re: '92 XP cavitation problem.

Also check leading edges of the blade are not dinged up this will cause loss of power also. If it has picked some rocks in the past the edges get dull and blunt, if so take out and use a file and sharpen the edges to almost a knife edge and then lightly sand back just a bit and you will find it will cut through the water and get more power.

Check the wear ring while you have it out for any gouges on the inside.



Regards Xdrian

[aphexandy]

Re: '92 XP cavitation problem.

The impeller in the '91 is stamped on the cone between each blade with " Skat-Trak720v" that is all I could see. Also, that impeller is in pretty rough shape as far as dings and such, but I havn't noticed a cavitation problem on that ski. the impeller on the '92 appears to be stock (non-polished stainless) and is in much better shape (as far as dings and such). that is the one giving me fits. as far as the rpm issue, my '91 revs to 6500 in the water, and the '92 will only get to about 6000 unless it cavitates (you all know the sound it makes) or leaves the water completly. I know one is a yellow and the other is a white, did they change the rev limit between '91 and '92?

[aphexandy]

Re: '92 XP cavitation problem.

One thing I thought of was the stator timing? as I said, I installed a new stator acording to the Clymer manual "initial timing". I know being out of time will effect my power, but what about top engine speed?