90-854785R1 – Mercury Mariner Service Manual 25HP Bigfoot 4-Stroke (1998)

The 90-854785R1 Mercury 25HP Bigfoot Manual provides official factory guidance for 25HP Bigfoot 4-Stroke outboards built in 1998. This manual is an essential reference for boat owners, mechanics, and marine technicians who need accurate service and repair information for Mercury and Mariner 25 Bigfoot models.

Published by Mercury Marine, the manual includes complete instructions for troubleshooting, maintenance, and repair of key systems. Sections cover the powerhead, ignition, fuel delivery, cooling, electrical wiring, lubrication, and midsection components. Clear diagrams, exploded views, and torque specifications are included to simplify service tasks.

One of the most important aspects of the Mercury 25HP Bigfoot Manual (90-854785R1) is its detailed coverage of the 4-stroke powerhead, cylinder head removal, and valve servicing. It also includes wiring diagrams, part breakdowns, and system operation explanations to ensure accurate diagnosis and repair.

This manual applies to United States engines with starting serial number 0G590000 and above. With clear step-by-step instructions and factory specifications, it guarantees that both professional workshops and DIY owners can maintain their outboards to factory standards.

Key Features:

• Part Number: 90-854785R1

• Models Covered: Mercury/Mariner 25HP Bigfoot (4-Stroke)

• Year: 1998

• Starting Serial Number: 0G590000 (U.S.)

• Detailed repair and maintenance procedures

• Exploded-view diagrams for part identification

• Torque specs, troubleshooting, and wiring diagrams

• Official Mercury Marine factory manual

At Arizona Outboard Dismantlers, we supply factory manuals and marine parts to ensure your engine stays reliable on the water. The 90-854785R1 manual is the definitive guide for maintaining and servicing your 25HP Bigfoot 4-Stroke outboard.