Yep I'd say lean, stays running before the engine unloads, it's turning a much lower rpm before it gets on plane so it isn't really starving for fuel, as soon as the engine unwinds it starts sucking in way more air, thats when it goes lean and dies. Turn out the needle a 1/4 turn and try it, it it acts the same make sure there is no congealed oil in the needle assembly of the carb, no leaks in the exhaust pressure or feed lines, should be no bubbles in the line from the tank to the carb when the engine is running. Check the inside of the tank if the problem persists, sometimes the brass tubes in the tank do crack.
I replace all my silicone fuel lines every spring, cheap and avoids potential problems, check the tanks over the winter, couple of years ago I found the remains of a spider and its web in a tank, would have really messed up a days running if I hadn't noticed it, it would have been the very last place I'd have looked for a problem because I would have had to pull the engine to get the tank out!
I've laughed at some of my nitro buggy buddies, with the flip top tanks and squeeze bottle fillers, fuel bottle lying on its side in the dirt, stuff all over the tip and they stick it in the tank and fill it up! Then complain when the engine won't stay running! Can't see the bottom of the tank through the dirt! clunk plugged solid!
You probably just need to richen it up a bit, unless it's completely worn out, then a piston and sleeve will set you back up, and cheap as well.
If it's new and all stock just go over the fuel lines make sure nothing got kinked somehow, these things are kinda finicky until they get broken in. I prefer to break in my engine on the water under load but I've got a fair bit of experience, For the first bunch of attempts at running a new boat I spend a lot of time paddling after stalled boats. I'd give it a good few starts and short runs at home dry, they will not instantly overheat and seize, if water sizzles off the head right away its too hot. you can rig up a gallon jug to cool it at home if your worried about it. Let it cool right down between runs, get a good few heat cool cycles into it.
Try a 1/4 turn out on the needle and check the lines.