Mr fixit is definately on the right track here it sounds more and more like a blocked fuel filter, if there is a fuel stop solenoid at the base of the carb which is subject to vacuum activation then if there is a gasket or manifold leak then this may should down as the vacuum falls thus stalling the engine. It may not have a fuel stop solenoid if not set the power mixture valve to the half way mark,
Screw the idle mixture screw up fully and then back of four turns and see if the engine will idle as this should give the engine a reasonably rich mixture if it still stalls out you will have to look for an air leak or a blocked filter.

Regards Titus