My YJ has been Nuttered. I am not sure the timing on the Jeep right now. I haven't checked it out. The nutter was done by previous owner. This symptom seems to come and go, but has gotten worse lately. When I start the Jeep after a couple or more hours of being turned off it idles very roughly to the point of dying or almost dying out before the choke will kick in properly. It shakes and stutters up until that point. If I try to press the gas pedal while it is doing this, it will spit and sputter and die. Once the choke kicks in the Jeep warms up and runs fine. No issues at that point.
What would cause this? Is there a simple solution?
My YJ had the hardest time starting as well. I ended up doing a rebuild kit in my carter, and re-timed it. Got rid of all the unnecessary vacuum lines and smog garbage. Many people here will tell you to junk the carter, or make a paper weight out of it, and get a motorcraft or any other carb. Carters are not the best, but since I rebuilt mine six months ago there have been no clogged idler tubes, flooding out, or hard starting. For 15-20 bucks it is worth a shot.
What is the idle at when it does run correctly? If it is too high it is actually bypassing the idle circuit IIRC. Truthfully, I would ditch the Carter but there are a few ppl on here that know quite a bit about fixing them. Mine started going out and I just found a Weber. Took all of about two hours to install and adjust and I don't regret it the least.
As BL907 said the cheapest fix would be a re-build...might be a float that is sticking occasionally. If you're comfortable with it, get a kit and strip it down and clean it really well. It's worth a try. I found my Weber on Craigslist for $125 with the Jeep conversion adapter.