Let me start by saying that I have not gotton my hands on the ski due to my 24 hour tour of duty,but this is what my friend states is wrong:He took the ski out today and was running fine for approx. 45-min, when it started running rough. He said it was sluggish at low end,and would not get to top speed. As he was riding back he stated the top end improved back to normal,but the low and was still sluggish. Seems maybe like plugs to me,but I just want to get some ideas for when I work on it tomorrow. Also should note that it is Stage I with the D-Plate,and water box dry mod from jet works. Thanks for all your help ahead of time.......

I guess I will answer my own question.There was a chunk missing out of the rear piston,in the pv area.The pv seems ok with the pin in securly.I however did order a new piston kit,and the performance valve kits for all three cylinders. No damage to head or cylinder.

Did you take the power valve out? Does it look shiney on the ends? Do the sides of the valve look like they were gouged? It sounds like you had a powervalve take out a ring. Did you do a compression check?

Did your jetski die when you tried to idle it? If so then you might want to take out those valves and look at them.

my bad.. If your head looks fine then it might be something else. Find the problem or you will have the same thing happen again. Water intrusion possible?