This manual covers the Mercury Mariner 40, 50, and 60 HP 4-Stroke EFI outboard motors manufactured in 2002 and newer. These engines are designed with advanced Electronic Fuel Injection (EFI) for reliable performance and efficiency, suitable for a wide range of boating applications. The engineering quality and inherent reliability of Mercury outboards are supported by this comprehensive guide, ensuring optimal operation for the intended user. The purpose of this Service Repair Manual is to provide detailed instructions and information necessary for the maintenance, diagnosis, and repair of your Mercury Mariner outboard. It includes essential sections on general information, installation, electrical systems, ignition, charging and starting, fuel injection theory, diagnostics, troubleshooting, and specific service procedures for various engine components including the powerhead, mid-section, and lower unit. High-quality diagrams and instructions are provided to assist Do-It-Yourselfers (DIY) and technicians.