I've seen this but from a partly-blocked main jet. If the throttle control stop is on the wrong side of the throttle stud, the governor can't control the throttle properly. Easy to reassemble it wrong. Check governor belt is in place and properly tensioned, check that when the throttle control is moved to full, that the governor control rod is free to open and close the throttle by hand. The throttle control when all the way out, pulls the throttle closed, against the governor spring.

That sounds good but also check when it's at partial throttle - the throttle tang should prevent the governor from opening the throttle right up. If it does that, then it's in the right relationship

Thanks for posting, love the photos. You should tie the machine down better, looks like the engine blew off!