I dont have a carbureted Jeep, (its an 86 Commanche with TBI) but anything with a carb is likely to need a rebuild on its carb every 10 to 15 years. If this will be the first rebuild for that carb, its certainly due. And for any engine with a carb, there isnt any other way for it to guzzle gas at an idle other than via a defective carb. It cold be a stuck float or one that has slowly filled with gas, or crud that is blocking the needle valve in the float chamber from filling, or....
I would presume the spark plugs are very black, even looking wet - and its hard to start because the idle mixture is too rich, and the plugs get fouled and then wont fire.
Be sure to have a good gasket at the base of the carb. I dont know about the 2 barrel ones, but on many 4 barrel carbs, there are vacuum passages that run along the bottom of the carb, and if the bottom gasket is ripped/shrunk/torn, the passage is opened up; and may be dribbling fuel into the intake manifold directly, instead of through the idle jets.
If the fuel pump is more than 10 years old, it might be a good time to change that too. I had a mechanical fuel pump whose little rubber diaphram began to disintegrate, feeding tiny rubber bits up to the carb - where they cause the needle valve to stick slightly open: And the engine would barely run due to being over-rich. Black smoke was visible from the exhaust pipe.
I have a 37 year old motorhome, and because it typically sits for 11-1/2 months each year, the carburetor gaskets shrink up and require replacement about every 6 or 7 years!