This is the Complete Carb 60RA for the O.S. 81FS-a Engine (OSMG0981). / / FEATURES: High Speed needle valve adjustment with a Low Speed mixture control / Rotary style throttle lever / Carb body is made of aluminum / / INCLUDES: One carburetor / Two carb retaining screws / / SPECS: Bore: 11.9mm (0.47") / Diameter: 15.3mm (0.60")