The throttle cable is like new and works smoothly. It looks like the mechanical link age is working. The engine appears to stay at max speed. I do not hear the engine speed up when I engage the mower. I used to always hear the govenor increase when the mower was engaged

Have you adjusted or removed the governor for any reason? If so, make sure to get it set back correctly. You generally loosen the governor arm lock nut, rotate the governor linkage to "wide-open", turn the governor control rod all the way in the same direction as you did the linkage, then tighten the nut down. This will get it "statically set". You will need a tool to adjust high and low rpm governor control based on what is recommended for your engine, but basically the "tool" bends the tang that is holding the governor springs.
Are you sure the blades are actually engaging?

Check the butterfly on the carb make sure the linkage is moving it .
The linkage can move without moving the butterfly.
Luck