honda gcv160 mower,rpm problem

I have a honda self propelled hrr2163tda mower with the gcv160 eng.This spring the rpm's started to rise and fall with the mower moving or not moving.At first I thought maybe the carb was plugged up so I removed it,soaked it in cleaner and reinstalled it with new gaskets.It ran better but the rpm problem was still there.Then after doing some research on line I replaced the spark plug ,again no improvement.I have found that if I force the govenor link to remain stationary that it will idle smooth.I have given the govenor link and springs a very close inspection and they all appear fine.I am certain I reattached it correctly to the carb when I removed it for cleaning.I feel like I've checked everything with no improvement but I must be missing something.Any ideas?

 

Mine does that when the air filter needs cleaning.

 

I would try cleaning carburetor again. This time disassembling it to better clean the internal passages & jets.

 

Soaked the carb overnight in a parts washer.Its running fine now.Thank you