This service manual covers Mercury MerCruiser marine engines, specifically models equipped with GM V8 454 CID (7.4L) and 502 CID (8.2L) engines. These robust powerplants are recognized for their dependable performance and durable construction, making them a popular choice for a wide range of marine applications. Designed for reliability and efficiency, these engines provide the power and longevity expected from high-quality marine propulsion systems.

This comprehensive manual is designed to assist owners, technicians, and mechanics in maintaining and repairing these Mercury MerCruiser engines. It details essential maintenance procedures, diagnostic troubleshooting steps, and provides critical technical specifications. By following the guidelines and instructions within this manual, users can ensure optimal engine performance, longevity, and safety for their vessels.