Kohler PA-ZT720-3016 Engine 1" x 3.16" Shaft Vertical Recoil Start 21 HPKohler PA ZT720 3016 Engine 1" x 3. 16" Shaft Vertical Recoil Start 21 HP Designed to get the job done reliably, Confidant engines are battle tested to meet KOHLER Command PRO durability tests. They feature a 3 year, unlimited hour, limited warranty. Features: Cast iron cylinder bores protect under dirty conditions High impact nylon shroud and valve cover protect against damage to internal components Chopper grass screen guard prevents grass and