Quicksilver 863674A04 Impeller Housing Cover Rear Cover Assembly MerCruiser Seawater Pump

The Quicksilver 863674A04 Impeller Housing Cover is an OEM rear cover assembly designed for the brass seawater pump used in MerCruiser MCM and MIE 496/8.1L sterndrive and inboard engines. This assembly serves as the rear end cap of the raw water (seawater) pump, sealing the impeller cavity and maintaining proper cooling water flow through the engine's cooling circuit.

Key Features:

• OEM Mercury Marine part — manufactured to factory specifications for direct replacement fit
• Brass pump housing construction for corrosion resistance in raw water applications
• Stainless steel wear plate included for extended service life and improved impeller sealing
• Designed for pumps with air fittings — compatible with brass seawater pump assemblies equipped with air fitting ports
• Replaces worn or damaged rear covers to restore proper pump operation and prevent cooling system leaks

This rear cover assembly is a critical component of the MerCruiser seawater (raw water) cooling system. Replacing a worn cover and wear plate helps ensure the impeller maintains proper contact and efficiency, protecting the engine from overheating. This is an OEM Quicksilver part backed by Mercury Marine's standard factory warranty against defects in materials and workmanship.

OEM Part Number: 863674A04