tellspin_37,

like bubbagates said, Remove both needles and clean them and the little screen on the pump side of the carb may be clogged as well. It might also be time to replace the diaphrams on both sides of the carb (both pump and pressure).

Open both the low and high needle valves 2 turns, next start the engine, let the engine warm up and give it full throttle. If it does not hesitate then lean the low end 1/8 turn and try again. Keep doing this until when you go from idle to full it hesitates and then richen it up 1/8. Now go to your high needle and with a tach tweak it until you get your highest rpm and then back it off 1/8 turn. If you are unable to do this because the engine simply will not respond then try changing the plug. If it has been setting around for that many years you may need to change some gaskets and clean it good.