This workshop service repair manual covers the Mercury Mariner outboard motor, specifically models with 25 HP ratings and serial numbers 0G044027 and above (US) or 09807909 and above (BE). Designed for reliability and performance, the Mercury Mariner series represents robust engineering for marine applications. This manual is intended to provide comprehensive information for the maintenance and repair of these powerful outboard motors. The purpose of this manual is to serve as a complete guide for owners, mechanics, and technicians. It details essential procedures, including routine maintenance, troubleshooting, and technical specifications. With hundreds of photos, illustrations, and detailed instructions, this resource ensures that all aspects of the Mariner outboard motor, from the powerhead to the lower unit, can be properly serviced. Key sections cover electrical systems, fuel systems, lubrication, and more, all presented with clear, numbered instructions and important safety notes.