This manual covers Mercury Marine In-Line Diesel Engines, including models with 2.8L and 4.2L displacements. These engines utilize Common Rail Direct Injection and are designed for robust performance in marine applications. Mercury Marine is recognized for its commitment to engineering quality and reliability, ensuring dependable operation for a wide range of boating needs. This documentation provides essential information for understanding and maintaining these advanced diesel powerplants. The purpose of this comprehensive manual is to serve as a primary resource for owners, technicians, and mechanics. It details general information, routine maintenance schedules, engine removal and installation procedures, and in-depth coverage of critical systems such as fuel, lubrication, cooling, intake, exhaust, and electrical. Extensive troubleshooting guides and detailed repair procedures are included to facilitate efficient and accurate servicing, ensuring the longevity and optimal performance of your Mercury Marine diesel engine.