This workshop service manual covers the Mercury Mariner 225 HP EFI Outboard engine. Designed for marine applications, this powerful outboard motor features electronic fuel injection for optimal performance and efficiency. Its robust V6 configuration and substantial displacement provide the reliable power expected from Mercury marine products, making it suitable for a wide range of boating activities. The engineering quality and inherent reliability of the Mariner series ensure consistent operation in demanding marine environments. This manual provides comprehensive guidance for the repair and overhaul of the Mercury Mariner 225 HP EFI Outboard. It details essential maintenance procedures, troubleshooting steps, and technical specifications necessary for proper upkeep. Owners, mechanics, and technicians will find the information invaluable for maintaining the engine's performance, ensuring longevity, and addressing any potential issues. The manual assumes a foundational understanding of general marine practices, offering detailed instructions to facilitate effective service and repair.