CJ7 bad idle and running rich

I have a 1983 Jeep CJ7 that has 146,000 miles. It has the 4.2 engine. The problem is that my engine would not idle along with no power at higher RPM's. I replaced the carburetor and had a mechanic check it out. The inspection tested that the fuel delivery was normal along with the volume. To-date the engine runs great at low speeds and then loads up at high speeds. I will shut off the engine and let it sit for 10-15 min. Re-start is tough and when it does fire up black smoke comes out the tail pipe. I called and just received another carter carb. Is there something else going on here? How can I resolve this problem. Oh I forgot to mention that I have no power to my auto choke wire. Not sure if it matters or where I should follow the wire for connection.

Thanks for your help.

Randy