No one asked this, so I will. And this is a very basic functionality. Are you getting adequate tank pressure? It may be leaning out after full throttle with inadequate pressure. Just a thought. I don't fly four strokes, although I did have an OS 52 Surpass for a short time and it ran just fine all the time I had it, so I am by no means an expert. But sometimes a basic question can help someone get through a problem. But what I do know about them is running them over about 10,000 RPM is not supposed to be very good for the engine, and for the reasons already mentioned by earlier posters.

Good luck with that. Let us know what you find when you do get it running right.

DS.