IMPULSOR YAMAHA 80/100 HP

Function and technical context

The water pump impeller is the fundamental rotating component of the cooling circuit in 80 and 100 hp Yamaha outboard engines. Made of high-resistance elastomer, its flexible vanes generate the necessary flow to suck water from the marine environment and distribute it through the internal galleries of the engine block, extracting the heat generated in the combustion chamber. Working housed in the water pump box located in the motor leg, it rotates integral with the control shaft to maintain the operating temperature within safe ranges. The deterioration or breakage of its vanes immediately interrupts the coolant flow, exposing the engine to severe overheating that can lead to internal seizure, melting of head gaskets and irreversible damage to the internal components of the engine.

When to replace this part?

The clearest symptoms of an exhausted impeller are the reduction or absence of the water jet in the engine discharge pipe, the activation of the high temperature alarms on the instrument panel and the appearance of smoke coming from the impeller area under sustained load. Elastomer vanes suffer permanent deformation and progressive loss of flexibility; Manufacturers recommend inspecting the impeller every 300–400 hours of operation and replacing it preventively every two seasons of heavy boating, regardless of the apparent visible condition of the vanes. On long-range voyages or navigation in waters with sediment and fine sand, carrying out preventive replacement is the safest and most economical decision in the event of a cooling system failure at sea.

Compatible Yamaha engines

Equivalent manufacturer part numbers