Cj has hard time going uphill when it's cold.

After sitting for a while my 1979 CJ 258 lags and sputters when going up a hill, it almost feel like it is suffocating and I have to blow out the extra gas out of the carb by taking it out of third and through it into second and hit the gas, while doing this black smoke comes out of the tail pipe with and a fluttering sound. Once it's warmed up after driving about 15 to 20 min it drives fine. Any thought. I have had it tuned to 15 inch of vacume and the timing was done. Is it still running to rich and how do I adjust that. Thanks

Cj has hard time going uphill when it's cold.