The 439077 Water Pump Impeller Kit by Serda-Marine-Parts is specifically designed for Johnson Evinrude engines with 35 to 60 HP. This kit includes the necessary components to repair or replace a faulty water pump impeller, ensuring optimal cooling system performance in your boat. With the manufacturer part numbers 391635 and 777808, this product is a reliable and high-quality choice for maintaining your outboard engine.