Gasoline Engine Engine Series Vanguard Gross Torque Not Applicable Horsepower 18 hp Shaft Orientation Horizontal Shaft Configuration 1-1/8 in Dia X 3.91/3.99 in Long 1/4 in Keyway 7/16-20 D T Shaft Diameter 1 1/8 in Shaft Length 4 in Start Type Electric Maximum Speed 3 600 RPM Muffler No CARB Compliant CARB Compliant Engine Brand Briggs and Stratton Engine Displacement 570 cc Engine Cycle 4-Cycle