98 Sporster performance

[Huddy]

I am looking for suggestions on how to improve the performance of my 98 sporster. The engines seem to run just fine but when I push it to full throttle both engines go to 7K rpm and it takes quite a bit of time for it to plane out and pick up speed. If I take my time going to full throttle it helps but it acts like once I get to a certain point something is slipping and it jumps to 7k rpms until it slowly gets up to speed. It's even worse when trying to pull a wake boarder or tube. I replaced the wear rings because they where way out of spec's hoping that I would get some improvement but I did not. With the 3 of us full tank of gas and a cooler our top speed is about 43mp on the gauge.

Looking for any suggestions.

 

[mlebauer]

that's cavitation as you probably know. I've got the same symptoms, just ordered rings from Parker Yamaha, hopefully they fix things for me. But there are other causes: leaking carbon seal, leaking drive shoe (the plate glued to the hull under the driveshaft), bad impeller. I'm going to go one step at a time, even though It may mean taking the pumps off repeatedly, unless the rings do it (hoping).