Sure sounds like it is leaning out on you at top end. Take the carb back off, remove the needle valve and force some fuel thru the carb. Make sure it flows well thru the spray bar in the carb. If blocked, clean it carefully. Reassemble all of the above and try to set the needle where it was before. Restart and test. If it still quits open the needle a few clicks and see if there is any improvement. You may just be too lean or picked up some trash in your fuel.