This service repair manual covers the Mercury MerCruiser #30 Marine Engines, specifically the 496CID / 8.1L Gasoline Engine. It details models including the 496 Mag HO (Sterndrive), 496 Mag (Sterndrive), 8.1S HO (Inboard), and 8.1S Horizon (Inboard). These V8 engines feature a 496 cubic inch (8.1 Liter) displacement and Electronic Fuel Injection (EFI), designed for robust marine performance. The manual provides comprehensive information for owners and technicians alike, highlighting the engineering quality and reliability expected from Mercury MerCruiser marine propulsion systems. The purpose of this manual is to provide detailed guidance for the maintenance, troubleshooting, and repair of the specified Mercury MerCruiser engines. It covers essential procedures such as removal and installation, disassembly and reassembly, and inspection and adjustment. Technical specifications, electrical system components (starting, ignition, charging), exhaust system parts, and power steering system details are also included. With included illustrations and zoom functionality, this English-language manual offers a thorough resource to ensure the optimal performance and longevity of your marine engine.