Briggs & stratton 44s977-0033-g1, gas engine professional v-twin, vertical shaft, 1-1/8″ crank shaft briggs & stratton vertical professional series engine is 724cc and 25.0 gross hp. This briggs & stratton v-twin has a 1-1/8″ x 4-5/16″ crankshaft and a 12v electric start with 16 amp alternator. briggs & stratton professional series engines deliver the reliable, efficient power needed for riding lawn mowers and tractors.