Use Udor's 5033.A4 Gearbox to attach diaphragm pumps to a gas engine with a one-inch shaft. This item can be used for 8 hp, 9 hp, 11 hp and 13 hp engines. In general, engine brands that can be used with this gearbox include Briggs and Stratton, Vanguard, Honda and Kohler Command. This gearbox is bearing supported and vented, providing a longer life and cooler operations.