Pcv Hose

so starting to narrow down my issue on my 75 CJ5, i unplugged the PCV hose and it started idling way better and basically started running as it should. still blowing back smoke so i am assuming the carb is to rich? as soon as i plug the hose back in to the valve it wants to die like its not getting enough air. the PCV is clean and can freely move. i have a new stock cab on the way and hope that clears it up. any other ideas what could cause this.

 

Black smoke is fuel. It should be accompanied by a rich exhaust odor. Black smoke at idle is usually caused by the float being too high, which floods the carb. Other possibilities are a bad power valve or incorrect reassembly after an overhaul.

PCV valve:
A metered vacuum leak designed to draw fumes out of the crankcase and burn them.
Given your excessively rich condition, unplugging the hose would allow more air in, leaning out the mixture and the engine would (theoretically) run better.

If it is a stock MC carb:
Remove the carb
Pull the lid
Inspect the needle and seat
Measure/adjust the float level
Pull the Power Valve cover and inspect for any fuel in it. If so, the valve is bad/missing.
Reinstall and start. adjust the idle mixture