42" Sears Lawn Tractor with Briggs&Stratton Model# 407777 type= 0174-E1?

I have a 46" deck Sears lawn tractor with a 20 HP B&S Mod 407777 Type 0174-E1 engine. A few weeks ago my tractor started stalling and eventually died. I have replaced the carburator, fuel lines, fuel filter, spark plugs, air filter, oil filter, and oil. After I put everything back together the engine was revving too high. I ahve checked all of the connection for the carburator and they seem to be correct. Specifically, the is the choke link that goes from the choke cable to choke on the carburator that is operating correctly and verified since when it starts if i use the choke I am able to slow the engine sown some by decreasing the amount of gas. The throttle link is hooked to the governor arm on the right side facing the tractor. I ahve run out of ooptions and I am ahvin g sears come service the tractor next week.

The throttle has no effect. The throttle cable is not slipping in the clamp and when it extends, everything seems to move freely.

I do not want to spend the money of there is an easy fix. Any suggestions on how to fix this?