Briggs & Stratton 19L232-0037-F1 Horizontal Engine, Vanguard Series, 305cc, 10.0 Gross HP, 1″ x 3-21/32″ Crankshaft, 7/16″-20 Drilled & Tapped, 1/4″ Square Keyway, Oil Sensor, 3.8 qt Fuel Tank