YAMAHA WATER PUMP KIT 6E0-W0078-A2

Function and technical context

This water pump kit is the central component of the cooling system on Yamaha outboard engines. The pump pushes seawater through the internal passages of the engine to extract the heat generated by combustion and maintain operating temperatures within safe ranges. Without a functional water pump, the engine loses its ability to dissipate heat, leading to rapid overheating, accelerated internal corrosion of the cylinders and cylinder head, and ultimately engine seizure. It is installed in the lower casing (motor base) and is an integral part of the salt water cooling circuit.

When to replace this part?

Typical symptoms of wear include weak cooling water flow (observable by the discharge jet at the stern), increased engine temperature on the dashboard gauge, and presence of water in the engine crankcase. The rubber impellers inside the pump suffer progressive wear due to abrasion with salt water particles and algae formation, losing elasticity and sealing capacity. It is recommended to check the condition of the pump every sailing season and replace the kit preventively every 500–800 hours of operation or every 2–3 years, whichever occurs first. Preventatively changing the pump before total collapse avoids much more expensive engine repairs and the possibility of being left without cooling at sea.

Compatible Yamaha engines

Equivalent manufacturer part numbers