[tsetsaf]

Sounds like a carb problem. Get yourself some carb cleaner, pull the air cleaner off, and do some spring cleaning. Make sure all the butterflies are moving freely and not sticking. At the same time check the various nuts and bolts on the carb and inspect for any leaks.

If the truck was sitting for a while and there was crap in the fuel lines you could have some dirt clogged inside the carb.

Probably not fuel pump as the truck will run. Probably not ignition for the same reason. The fact that you are able to fire it up with the choke on vs off tells me it is carb related. If the vehicle is a new purchase you may want to take the time to go through all your vital systems and clean them up including:

-oil/ oil filter
-brake fluids/ pads
-tranny fluid/ filter
-spark plugs/ wires/ rotor/ cap
-electric grounds

I ignored a small problem like yours when I took over my 71 and nearly got killed when the master cylinder failed on the freeway!