My NS70A2 cuts outs and sputters before it plains out, I have pulled the carbs and cleaned them did not completely disassmble them took bowls off and cleaned them the best I could they did not look gummed up. Took the cover off and played with a rod in front of the throttle rod and got it to smooth out and run well as long as I held it in a certain position. Any ideas what could be wrong????