The Mercury MerCruiser 305 CID engine, produced between 1998 and 2001, represents a robust V8 gasoline power plant designed for marine applications. This engine family, displacing 5.0 liters (305 cubic inches), typically offers a power output ranging from 200 to 250 horsepower, depending on the specific configuration. Featuring a cast iron block and cylinder heads, it is engineered for durability and reliability in demanding marine environments. Depending on the exact model, it may utilize either a carbureted or fuel injection system, paired with an electronic ignition for efficient operation. This engine is commonly found paired with a sterndrive transmission, such as the Alpha One or Bravo One, with gear ratios varying by drive unit. This Service Repair Manual provides comprehensive guidance for the Mercury MerCruiser 305 CID engine, covering all service and repair procedures in English. It is an essential resource for owners, mechanics, and technicians, detailing maintenance schedules, troubleshooting techniques, and technical specifications necessary for optimal performance and longevity. Key areas addressed include lubrication requirements, cooling system maintenance, fuel system servicing, and filter replacement. The manual outlines recommended service intervals for oil changes and spark plug replacement, along with specific details on oil capacity and the recommended SAE 25W-40 marine engine oil, ensuring proper upkeep of this powerful marine engine.