Tecumseh Hmsk80-155693x 8hp Engine Horizontal Shaft UsedTecumseh model # HMSK80-155693X 8 HP Engine. Crankshaft is 3 3/8 Long overall. First 1 11/16″ is 1 3/8″ in diameter, next 1/2″ is 1″ in diameter, last 1 3/16″ is 3/4″ in diameter. It is tapped and keyed. Reverse crankshaft is 1″ long, 5/16″ in diameter, tapped.