This manual covers Mercury Mercruiser GM V8 marine engines, specifically the 305 CID (5.0L) and 350 CID (5.7L) models produced between 1998 and 2006. These engines are known for their robust construction and reliable performance in marine applications. This guide is designed to provide comprehensive information for the maintenance and repair of these gasoline-powered V8 marine engines, ensuring their continued optimal operation. The purpose of this OEM shop, service, and repair manual is to equip owners, mechanics, and technicians with the necessary knowledge for effective vehicle upkeep. It details general information, routine maintenance, engine removal and installation, fuel systems, lubrication and cooling systems, engine specifications, transmission and drive components, steering systems, body work, intake and exhaust systems, and the electrical system. Additionally, advanced troubleshooting procedures are included to assist in diagnosing and resolving potential issues.