99 Speedster intermittant power with high RPMs

[BigDaddyPM]

I bought my Speedster last year and have not been able to figure out, nor my mechanic, what is causing my power issues. It starts up right away and runs great for a random amount to time, then experience what feels like cavitation for a random time while RPMs in both engines remains constant at 6500 RPMs, then power comes back and runs great. Last year, once, while no power the boat beeped and the mechanic fixed the governor. Hasn't beeped since but still power problems. I did not find any discussions but please refer me to any links discussing this. Please let me know more information needed.

Thanks for your time and consideration.

 

[mikidymac]

You don't have a governor so not sure what the "mechanic" did.

You need to see if it is cavitating or loosing power. Cavitating is pump related and loss of power is typically dirty carbs/fuel system.

 

[BigDaddyPM]

Thanks! If your riding along 40mph and 6500 rpms and boat drops to 15-20 MPH @ 6500 rpms then I assume cavitation. But what would cause it intermittently?

 

[mikidymac]

Yes, same rpm but loss in speed would be cavitation.

Typical places are pump to hull seal and driveshaft seal.