90 yj only 70k on it sat for 2 years. 4.2 carb, ran one day now hard start, runs for 15 min. then dies. cant restart unless kept in start position. not ign. switch, fuel pump, cap, rotor, wires, plugs, or pick up coil in dist.?

Check the fuel for a presence of water. I'm sure there was a recall notice on the gasket on top of the fuel tank where the sending unit mounts. My YJ sat for a year and had water in the tank from this leaking. Drain and drop the tank, replace the gasket, and reinstall.