[asphaltgambler]

Definitely running lean on low speed circuit. Check for adequate fuel delivery first (as said above) then try this trick. With air filter off, full throttle and RPM's quickly cover the throat of the carb with your palm until it almost quits. It may take a few repeat attempts but it works frequently enough and takes little effort. By doing this it creates an incredible suction on the fuel jets and emulsion tube and will sometimes pull the debris / gum through.

If this does not work, locate the low speed mixture adjustment screw (it should have one) turn the screw clockwise and count the number of turn until lightly seated. Remember this number. Now screw counter-clockwise until the screw / spring comes out. Take an aerosol can of carb cleaner / gum cutter, attach the little red spray tube and spray liberally into the hole where the screw was. Then blow through it lightly with shop air. Re-insert the screw and spring turning clock-wise until it seats. Then remembering the amount of turns prior, go counter clock-wise. This should do it. If not you'll need to remove the carb assy, disassemble to clean.