high speed cavitation

[Tom R]

Recently I had my 98 Sugar Sand tuned. For the past two weeks it has run as fast as when it was new, hitting 5300 rpm and 40+ mph. Suddenly everything has changed The engine revs to 2000 RPM max and won't go up on plane. It runs fine at low speed but when I advance the throttle it sounds like it is cavitating. The only thing that has changed is I went through a small area where there was vegetation just below the surface. I did a visual of the intake grate, (there was a small quarter sized rock lodged in the grate) forward view of impeller and stern view of impeller. Nothing looks clogged. Any suggestions

 

[njmr2fan]

Is it possible that a smaller rock made it through damaging the impeller?

 

[Bruce]

It could be something as small as some of that vegitation or fishing line wrapped around the impeller shaft. I would check the pump again.

 

[Cobra Jet Steering LLC]

If you sucked up a rock you hit bottom so there is probably more trash between the impeller blades, you just can't see it or you damaged the pump bearings.