This manual covers the Mercury Mercruiser 454 CID marine engine, produced between 1993 and 1997. This V8 engine, with a displacement of 454 cubic inches (7.4 liters), was engineered for reliable performance in marine applications, typically delivering between 300-350 horsepower and 400-450 lb-ft of torque. It features electronic ignition and can be equipped with either a carbureted or fuel-injected fuel system, paired with a marine gearbox for stern drive or inboard configurations. The robust construction and proven design of the 454 CID engine ensure dependable operation for a wide range of boating activities. The purpose of this Factory Service Repair Manual is to provide comprehensive guidance for the maintenance, repair, and troubleshooting of the Mercury Mercruiser 454 CID engine. It details essential procedures, including lubrication with SAE 25W-40 marine oil and maintenance of the cooling and fuel systems. Technical specifications, such as electrical system details and filter part numbers, are included to assist owners, mechanics, and technicians. By following the instructions within this manual, users can effectively preserve the performance and longevity of their marine propulsion system.