It sounds to me like your engine is sucking air from some place beside the carb.

The back plate may have loosened from the crankcase

The carb is held on by two sheet metal screws, it may have loosened.

The butterfly my have come loose from the shaft in the carb.


Your reed valve may be partially sprung but I doubt it.


you may also check your magneto and spark plug gaps.


But the most likely cause is the AIR LEAK!

I have one that was originally a Lawn Boy. But its a Ryobi if there ever was one. It also does 7100 with a 16-10. It still runs OK. They do a lot better with a carb from the Zenoah 23 on them but are perfectly usable as stock.


Enjoy

Jim