it could be the main jet but before i changed it i would mess with fuel air mixture screw i cant remember but i think it means rich also do a sparkplug check
ok its the tube in front on bottom of carb longest one it has a flat head screw u will need a small screw driver i used like a small screwdriver piece but turn it left but i would find out cause im not 100 percent sure but u can try just turn in a lil at a time