90-857046 – Mercury Mariner Service Manual 30–40HP 4-Stroke (1998)

The 90-857046 Mercury 30/40HP Service Manual  provides factory-authorized repair and maintenance instructions for 30HP and 40HP 4-Stroke outboard engines manufactured in 1998. Created by Mercury Marine, this manual is a trusted resource for boat owners, mechanics, and marine service centers.

This detailed manual covers all major systems, including ignition, fuel delivery, cooling, electrical, lubrication, and gearcase assemblies. Clear diagrams and exploded parts illustrations make identification and servicing easier. Torque specifications, wiring diagrams, and troubleshooting guides are included to ensure accurate, reliable repairs.

The Mercury 30/40HP 4-Stroke Manual (90-857046) also includes detailed instructions for cylinder head servicing, valve adjustments, and complete powerhead disassembly. It guides the reader step by step through procedures, minimizing guesswork and ensuring factory-standard accuracy.

This edition applies to U.S. engines with serial numbers 0G760300 and above. With more than 300 pages of technical detail, this service manual is indispensable for both professionals and DIY boaters who want to maintain their Mercury Mariner 4-Stroke outboards in peak condition.

Key Features:

• Part Number: 90-857046

• Models Covered: Mercury/Mariner 30HP and 40HP (4-Stroke)

• Year: 1998

• Serial Range: 0G760300 and above (U.S.)

• Detailed repair, service, and troubleshooting procedures

• Exploded-view diagrams for part identification

• Torque specifications and wiring diagrams

• Official Mercury Marine factory publication

At Arizona Outboard Dismantlers, we provide original manuals and marine parts to keep your outboard running strong. The 90-857046 Mercury 30/40HP Service Manual is a vital reference for ensuring your 30–40HP Mercury Mariner 4-Stroke performs at its best.