90-826148R1 Service Manual – Mercury/Mariner 30-40HP (2-Cylinder)

The Mercury 30-40HP Service Manual (part number 90-826148R1) is the official factory guide for 2-cylinder Mercury and Mariner outboards including Marathon and Sea Pro models. Printed in the USA by Mercury Marine, it provides detailed procedures for maintaining and repairing engines with U.S. serial numbers 0G044027 and up.

Inside this manual, you will find factory-approved steps for cylinder block service, crankcase inspection, connecting rod checks, lubrication systems, fuel delivery, and ignition timing. Every repair task is illustrated with exploded diagrams and includes torque specifications, tolerances, and dimensional data to support accurate servicing. The logical layout allows you to move from disassembly through inspection and reassembly with ease.

This guide also contains troubleshooting charts, diagnostic tips, and maintenance schedules designed to prevent failures and restore peak performance. Because the instructions come from Mercury engineers, they ensure your work meets original equipment standards – delivering reliability and extended engine life.

Built with a durable workshop-ready format, the Mercury 30-40HP Service Manual is essential for marine mechanics, professional technicians, and hands-on outboard owners alike. Whether you're rebuilding a powerhead or simply replacing seals, this manual provides the confidence and precision needed for proper results.

Arizona Outboard Dismantlers provides genuine manuals like this to help you protect your investment and keep your engine running season after season.