Cub Cadet RZT42 Zero Turn Mower Parts The Cub Cadet RZT42 is a residential zero turn mower with a 42" mowing deck. Genuine replacement parts for this mower can be found and purchased right here on cubparts . Either a Briggs & Stratton engine or a Kohler engine powers most RZT42's. Cub Cadet RZT 42 Manuals - Cub Cadet Parts n More Your Cub Cadet products come with years of experience in designing some of the most technologically innovative and customer-focused equipment available. Your RZT42 model is fit with a 20HP single-cylinder Kohler engine and a 42" mower deck.