Hi,i've just bought a '98 model GP800.The damn thing cavitates madly when i accelerate from a standing start.Over 20mph it's ok and hooks up.The prop is a solas 15/19 in good nick.Prop clearance is around .45mm.I'm running a toploader scoop as well.It's worse when i'm in the surf riding through the whitewater.I've also tried sealing the edge of the intake mouth to hull,without any difference.Thanks for any suggestions.

What are your mods? Solas recommends a 15/19 for a limited set up. What is the condition of the wear ring (impeller housing)? If it has any damage that will cause cavitation. Is the impeller nose cone in place? What about the pump stator veins? Are they all there and in good shape? Any damage to even one will cause cavitation.


With the GP style intake tracks you need to make sure they are sealed very well. This includes the pump inlet where it meets the hull. You might need to remove it completely. In fact, I suggest doing so. Use a quality marine-grade silicone designed for use below the waterline. Let it cure for at least 24 hours. Make sure you seal the intake grate everywhere it meets the intake track as well as all the pump sections.

Don't ask me why, but a 3 or 5 degree exit nozzle and a ride plate will fix it. REXA

install pump seal kit
make sure wear ring isn't scored too bad
also the seal between the shoe and the ride plate should have a lot of below the water line sealant i learned that the hard way....lol