This repair manual covers the Mercury Mariner 40, 50, and 60 EFI 4-Stroke outboard engines. These engines are engineered for reliable performance and are designed to meet the demands of various marine applications. Their 4-stroke EFI technology ensures efficient operation and power delivery, making them a robust choice for boaters. This comprehensive English-language repair manual provides detailed guidance on maintenance, troubleshooting, and technical specifications. It includes in-depth coverage of general information, routine maintenance, engine systems, fuel and lubrication, cooling, electrical systems, and advanced troubleshooting. This manual is an essential resource for owners and technicians to ensure the optimal performance and longevity of their Mercury Mariner engines.