I'm kinda at a loss with this ski. For the first two minutes of run time (after a couple minutes of warm up) it runs great, revs right up to about 6500 rpms and pulls out of the water nicely.I can get about 70 km/h (43ish mph) when it's cool/ within 5 mins of initial startup. after about 5 mins, the ski starts to misfire at high rpms and will only rev to about 5800-6000. the ski kinda breaks up at high rpms and wont pull out of the water properly if i stop.

Funny thing is, if i shut it off for 10 mins then restart, it runs great for about the same length of time. One rip up the river and then it's back to missing/ cutting out at high rpms.

Carbs cleaned
plugs replaced
Pump removed and inspected