xp800 bogging

Hey everyone, been struggling to get my last issue worked out of my ski. So i got a problem with the ski stalling if i gun it from idle. But if i kinda play with it a bit to get it over 3000rpm or so it will run fine. If i pull the choke half way and release it really quick it will not stall and...

So at the cottage working on a friends 96xp First test run - I started it up, started fine, let it warm up for about 30s tried to get on plane, bogging and when I gave it lots of throttle it had lots of cavitation, just revving. So took it slow and got on plane. Ran ok top end no hesitation...