This workshop service repair manual covers Mercury Mercruiser Marine Engines with the ECM 555 generation. These engines are engineered for reliable marine performance. While specific production years are not detailed, the focus on the ECM 555 system highlights advanced engine control for its intended applications. This comprehensive English-language manual provides essential information for servicing and repair. It includes detailed sections on general information, diagnostics, and troubleshooting procedures. The manual is designed to assist owners, mechanics, and technicians in maintaining the optimal performance and longevity of their Mercury Mercruiser marine engines.