This Service and Repair Manual covers the Mercury MerCruiser V8 Engine Lineup manufactured between 1985 and 1988. These robust V8 engines, available in displacements ranging from 305 to 540 cubic inches, were engineered for marine applications, delivering reliable performance across a variety of boating needs. Featuring advanced systems such as electronic ignition and typically marine closed cooling, these engines are designed for durability and power, with estimated horsepower and torque varying by specific configuration. The stern drive and inboard-outboard drivetrain options, paired with marine gear transmissions, provide efficient power transfer for a superior boating experience. This comprehensive manual provides essential information for the maintenance, repair, and technical understanding of your Mercury MerCruiser V8 engine. It details routine service procedures, including recommended oil types and capacities, spark plug specifications, and fuel and coolant requirements. Furthermore, the manual covers critical technical specifications, troubleshooting guidance, and safety protocols necessary for proper operation and longevity. Owners, mechanics, and technicians will find this English-language resource invaluable for ensuring the optimal performance and reliability of their 1985-1988 Mercury MerCruiser V8 engines.