I have about 60. I bought two at the same time used from fresh water. The other one actually has about 80 hours and is quite. I took out the bearing tube, jet pump coupler etc. and inspected. I couldn't see a problem with any of my seals or bearings.... all are clean and tight. I repacked the bearing with fresh grease, However when I put it back together I took it on a 50 mile ride and it was whining again when I took it out of the water???? Doesn't seem to be getting louder, just louder than the other ski. I think the noise is coming from the jet pump. I have good clearance on the impeller. May just keep riding and pay attention to see if it worsens?