Hello. 
One thing to look at while you have the carb off would be the condition of the little holes that the idle air/fuel adjustment screws seat into. Sometimes people get the idea that 'run the screws all the way in until they are seated, and then back them out a turn and a quarter' means to tighten those screws until you have nearly stripped the threads. If the guy down at Magilla Automotive has worked on this carb, it could be that those holes are all beat up and it is not possible for the needle to seal the hole.
One thing to look at while you have the carb off would be the condition of the little holes that the idle air/fuel adjustment screws seat into. Sometimes people get the idea that 'run the screws all the way in until they are seated, and then back them out a turn and a quarter' means to tighten those screws until you have nearly stripped the threads. If the guy down at Magilla Automotive has worked on this carb, it could be that those holes are all beat up and it is not possible for the needle to seal the hole. 
