This workshop service repair manual covers the Mercury Mariner 30JET HP outboard motor, a robust 4-cylinder engine designed for reliable performance. Engineered for demanding marine environments, this motor emphasizes durability and efficiency, making it a trusted choice for various boating applications. Its straightforward design and quality construction ensure dependable operation, providing boaters with the confidence needed for their time on the water. This comprehensive manual provides essential information for the service, maintenance, and troubleshooting of your Mercury Mariner 30JET HP. It details critical procedures, including engine disassembly and reassembly, lubrication, cooling system maintenance, fuel and ignition system servicing, and electrical system checks. With clear instructions and technical specifications, this guide is an indispensable resource for owners and technicians alike, enabling proper upkeep and efficient repair to maximize the motor's lifespan and performance.