Briggs & Stratton 33R877-0003-G1 540cc 19 Gross HP Intek Vertical OHV Engine with 1-Inch Diameter by 3-5/32-Inch Length Crankshaft Tapped 7/16-20-Inch Dura-Bore cast iron cylinder sleeve for extended life Float carburetor for consistent, easy starting Dual-Clean air cleaner pleated paper filter with a foam pre-cleaner ensures maximum protection for extended engine life Overhead valve design (OHV) for cooler operation and longer valve life Patented linear balancing system provides smoother performance