what do you thinks wrong with this

found this vid on internet just wondering what your opinions are on it

 

Its not jetted right..

 

or could the pilot jet be blocked

 

Tempted to say main tbh but hes revving it in a funny way and its on the stand so its slightly hard to pinpoint from the vid alone.

You can see up to a point (looks to be about half throttle) its picking up sort of cleanly though so it cant be too far off on the bottom end (probs get away with a bit of mixture adjustment). If the pilot was blocked it would be dying with a tiny bit of throttle which its not. If it was a wrong pilot (which rarely is a problem) it would be bogging down low aswell.

To diagnose bad running (especially when making a vid) you'd want to hold it at different positions for a moment atleast to get a real idea. It doesn't look like he even fully opens the throttle ever

I dont know how much if any of this applies to a 4 stroke though