This manual covers Mercury Mercruiser IN-LINE Diesel D-Tronic engines, specifically the 2.8L and 4.2L models, applicable to serial numbers D2.8L D-Tronic 0K000001 and Above, and D4.2L D-Tronic 0K000001 and Above for both Sterndrive and Inboard configurations. These turbocharged, in-line diesel engines feature the advanced D-Tronic electronic injection system and are designed for reliable marine propulsion. This Service Repair Manual provides comprehensive guidance for maintaining and repairing your Mercury Mercruiser IN-LINE Diesel D-Tronic engine. It includes detailed information on general maintenance, scheduled service, troubleshooting, fuel system service, cooling system maintenance, and electrical system upkeep, covering starting, charging, glow plugs, and instrumentation. The manual also details drive system components, including ZF/Hurth transmissions and propeller shaft models, as well as power steering systems. With illustrated, step-by-step instructions, component breakdowns, wiring diagrams, and zoomable exploded views, this manual is an essential resource for owners and technicians to ensure optimal engine performance and longevity.