Yamaha Water Pump Impeller (SE-50X-1) YJA-01135-32-03. Overview. The Yamaha YJA-01135-32-03 Water Pump Impeller (SE-50X-1) is a genuine original equipment manufacturer component designed to circulate cooling water through the engine and maintain proper operating temperature. The impeller is a critical component of the water pump system, using flexible blades to draw water from the lower unit and push it through the engine's cooling passages.. A properly functioning impeller ensures consistent wa