This service repair factory manual covers the Mercury MerCruiser IN-LINE Diesel D2.8L D-Tronic and D4.2L D-Tronic marine diesel engines. Designed for marine propulsion, these engines utilize diesel fuel and are engineered for reliability and performance. The manual specifically addresses sterndrive and inboard models from serial number 0K000001 and above, providing comprehensive information for these powerful and efficient marine powerplants. The purpose of this manual is to provide detailed guidance for the maintenance, repair, and servicing of your Mercury MerCruiser diesel engine. It includes step-by-step repair instructions, comprehensive coverage of engine mechanical systems, electrical systems, fuel, cooling, intake, exhaust, drive, and power steering systems. With zoom capability and part number references, this English-language manual is an essential resource for owners, mechanics, and technicians to ensure optimal performance and longevity of the marine diesel engine.