Hi,
First time posting here (been watching this forum for a while) so take what I say with a grain or two of salt,
Can you still control the engine speed at all with the throttle lever? This may indicate where the problem is.
I would definitely check the linkage between the governor and the carburetor. If you find that this linkage does not move then you will need to isolate which part is at fault by disconnecting the linkage from one end or the other.
Regards,
RLP
