Ed,
I would pull the carburetor to clean & inspect, then start it again to see what I had with the motor. Looking at your pics, I would be suspect of all work done by the previous owner & the very high idle could just be from the carb. If memory serves, the slide will fit in the carburetor ABOVE the throttle position sensor (throttle would be 3/4 open always) & would cause your symptoms.
Keep us posted,
DoldGuy