Used Tecumseh HSSK50-67368M 5HP horizontal dual shaft engine. Good engine may need carb work. Crankshaft is 3 3/8 long and is stepped. 1st 2 3/4″ has 1″ diameter; end has 7/8 diameter. It is keyed and tapped. Reverse crank is 1″ long with a 1/2″ diameter, it is keyed and tapped and the end is squared off.