DRAIN SCREW 22-479452

Function and technical context

The M14 x 12 millimeter drain screw is an essential component in the water evacuation systems of Mercury, Mariner, MerCruiser, Parsun, Yamaha and Tohatsu marine engines. This threaded plug guarantees the tightness of the engine block drain pipe, preventing salt water infiltration into critical areas where lubrication and cooling systems are housed. Its function is to allow controlled emptying of residual water from the engine after operation, while maintaining a tight seal when mounted. A leak or corrosion at this point causes water to enter internal cavities, accelerated deterioration of metals and compromises in the cooling capacity of the system.

When to replace this part?

This type of drain screw must be checked during each seasonal maintenance or after prolonged stranding, since marine corrosion and saline deposits progressively deteriorate the thread and seal. Common symptoms include visible drips at the installation area, rust deposits around the drain hole, or difficulty screwing it in without forcing. It is recommended to replace preventively every two seasons or whenever corrosion is detected, to avoid costly repairs due to water entering the engine. A new part with material resistant to marine corrosion prolongs the useful life of the cooling system and guarantees maintenance without surprises while sailing.

Engine Compatibility

Mercury/MerCruiser

Equivalent manufacturer part numbers