Leaning it out a bit could be a good idea but I don't think that's the problem. It might also be too lean and engine dies at high temps lacking of compression. If everything is ok (car doesnt spit out unburn oil from the exaust and also always blue smoke comes out of it) then your problem might be the low speed needle. Too rich low speed needle setting can cause stall when Idling for a long time and also too lean can cause overheating.