This Service Repair Manual covers Mercury Mariner 30/40 4-Stroke EFI Outboards, including models 150/175/200 EFI, starting from the 2002 model year with serial number 0T409000. These engines are engineered for reliability and performance, featuring Electronic Fuel Injection (EFI) for efficient operation. This manual provides comprehensive information for maintaining and repairing these robust marine engines, ensuring their continued optimal function. The purpose of this manual is to provide detailed guidance for service and repair. It includes high-quality diagrams, troubleshooting procedures, and in-depth instructions for all major engine systems, such as the powerhead, cylinder head, lubrication, and lower unit. This resource is designed for do-it-yourselfers and technicians alike, offering the most complete information available to keep your Mercury Mariner outboard running smoothly and efficiently.