Briggs & Stratton 21R707-0086-F1 vertical Intek engine is 344cc and puts out 10.5 HP (maximum horsepower). This Intek has a 1″ x 3-5/32″ crankshaft with a 1/4″ keyway and is equipped with a 12V electric starter and fuel tank. This model replaces 217907-4028-F1. Briggs & Stratton Intek engines feature dependable components such as Dual-Clean air filters, Dura-Bore cast iron sleeves and linear balancing systems that offer maximum protection, extended life and smooth performance in tough conditions. Designed for riding mower applications. Buyer protection package provides two-year limited consumer engine warranty. 50-State CARB Compliant. All engines purchased from us ship for free and are foam packed for added protection during transit.