Too rich quick fix....

I would try inserting a restrictor into the idle feed restriction to lean the mixture in the idle and transision circuits before doing anything else. I would start with a small piece of wire, something around .012 or so. Take a piece of stranded copper wire and use one of the strands. It's easy to insert a piece about 1/2 inch long through the hole and then bend it so that it stays in place. Put the carburetor back together and try it, see if it wants to surge (too lean) or it's much better(most likely). You will have to adjust the idle screws slightly farther out to compensate but not much. You might want to experiment with a larger or smaller wire depending on what it wants till you get it just right. This is VERY important because it saves gas and wear on the engine by having the transision circuit right. Another fact to remember and it's something that many folks over look is that the idle and transision circuits are ALWAYS working. Even at wide open throttle they are still a part of the picture. Their influence becomes less and less but it's still in there so therefore it pays to get it right or at least much closer.

This is an easy mod to try because it's easy to undo and it won't involve modifying anything on your carburetor.