This workshop service repair manual covers the Mercury Mariner EFI Outboard engine, a powerful 225 HP motor designed for demanding marine applications. Known for its robust engineering and reliable performance, the Mariner series represents a commitment to quality and efficiency in outboard propulsion. This manual provides comprehensive information to ensure optimal operation and longevity of your Mercury Mariner engine. This English-language workshop manual offers detailed guidance for maintenance, repair, and troubleshooting. It includes step-by-step instructions, hundreds of photos and illustrations, and specific sections on electrical system troubleshooting, fuel injection, powerhead, mid-section, and power trim. With a focus on safety through notes, cautions, and warnings, this printable manual is an essential resource for owners, mechanics, and technicians seeking to maintain and repair their Mercury Mariner EFI Outboard engine.