I have a friend that has a 1992 4.3liter Merc. with a 2 barrel carb, that will start fine, but will only run for about 1 min. sometime 2mins. then cuts off. When it does cut off it will restart right away, but will only run for a min or two. Does anyone have a idea what I can look for? Thanks in advance.

Same problem a friend had with a 97 4.3 his was a bad oil pressure switch. I believe they called it the Hobbs switch...? Same symptoms as you're describing... Might be worth checking out.

Fuel tank pick up tube could be clogged, had that happen to me years ago soon as engine stalls whatever is in the tank drops back out of tube. And would restart until it got cloogged again

Great advice guys, thanks