This workshop service repair manual covers the Mercury Mariner 225 HP EFI outboard engine, applicable to all models and engines. Engineered for robust performance, this naturally aspirated, water-cooled V6 engine delivers 225 horsepower through an Electronic Fuel Injection (EFI) system. Its design emphasizes reliability and power, making it a capable choice for various marine applications. The outboard lower unit with propeller provides efficient propulsion, while the typical alternator charging system ensures consistent electrical power. This comprehensive manual provides essential information for the maintenance, service, and troubleshooting of your Mercury Mariner 225 HP EFI. It details critical procedures, technical specifications, and recommended practices to ensure optimal engine performance and longevity. Whether you are performing routine maintenance, diagnosing issues, or undertaking more complex repairs, this guide serves as an indispensable resource for owners and technicians alike, written in English for clarity and ease of use.