Impeller 777212

Function and Technical Context

The water pump impeller is the rotating component responsible for driving the coolant fluid through the cooling circuit of an outboard or inboard engine, drawing water from outside and circulating it through the engine block to dissipate heat generated during combustion. Manufactured from flexible rubber, its vanes bend as they rotate within the pump housing, generating the flow rate necessary to maintain operating temperature within safe limits. Reference 777212 (REC777212) is compatible with Mercury/Mariner/MerCruiser reference 802334 and with OMC references 0777212, 385528, 389642 and 777212, making it a broad-spectrum component for Johnson and Evinrude engines, as well as the Mercury range. If this impeller wears or breaks, the pump stops circulating cooling water, causing engine overheating within minutes and potentially causing serious and irreversible damage to the cylinder head, gaskets and block.

When to Replace This Component?

The most common symptoms of a deteriorated impeller are the absence or reduction of cooling water flow at the engine outlet, the illumination of the temperature warning light or the activation of the overheat alarm system. The rubber vanes lose elasticity and develop cracks with use, heat exposure and dry storage periods, which is why manufacturers and marine service centers recommend preventive impeller replacement every 100-200 operating hours or at the beginning of each season for intensively used engines. Replacing the impeller preventively during annual maintenance is the simplest and most economical measure to avoid an overheating failure at sea.

Compatible Johnson/Evinrude Engines

Equivalent Manufacturer References