The Mercury Mariner DFI Optimax Outboard, produced between 2000 and 2005, represents a generation of advanced marine propulsion. Available in 115 HP, 135 HP, 150 HP, and 175 HP variants, these engines feature Direct Fuel Injection (DFI) technology for enhanced efficiency and performance. Their robust engineering ensures reliability for a wide range of boating applications, from recreational cruising to demanding commercial use. The Optimax DFI system, coupled with a CDI ignition and oil injection, provides a powerful and dependable marine experience. This Factory Service Repair Manual provides comprehensive guidance for the maintenance and repair of your Mercury Mariner DFI Optimax Outboard. It covers all essential aspects, including detailed technical specifications, scheduled maintenance procedures, advanced troubleshooting guides, and step-by-step repair instructions. With hundreds of pages of content, including all necessary illustrations, diagrams, photos, and wiring schematics, this manual is an indispensable resource for owners, mechanics, and technicians seeking to maintain the optimal performance and longevity of their outboard engine.