Mercury 225 EFI & 250 EFI Outboard Service Manual (1997 Edition)

Official Mercury 225 EFI and 250 EFI Service Publication

• Covers 1997 Mercury 225 EFI, 250 EFI, 3.0 Litre Marathon, and 3.0 Litre SeaPro outboard motor configurations
• Official Mercury Marine publication P/N 90-822900R3, dated December 1997
• Includes 12 wiring diagrams, 9 diagnostic troubleshooting flowcharts, and extensive torque specification tables
• Access the information instantly — no shipping wait — the PDF is available immediately after purchase
• Indexed PDF search covers every chapter and appendix
• Stored against your account so you can retrieve it after a hard-drive loss
• This 1997 edition is the base technical reference for the 3.0 Liter V-6 outboard family, featuring specific settings for EFI and carburetor setups

Technical Content and Procedures

This manual provides comprehensive technical guidance for maintaining and servicing Mercury outboard engines. Chapters are organized by system, starting with crucial information on specifications, routine maintenance schedules, and correct installation. The documentation details electrical systems, including ignition timing, stator diagnostics, and charging system troubleshooting. Fuel system coverage encompasses both EFI electronic components and carburetor adjustments, offering a thorough breakdown of jet sizing, float settings, and fuel pressure requirements. Powerhead and mid-section service information is included, along with detailed lower unit gear case specifications.

Specifications and Technical Data Preview

Technical data is presented through high-depth reference charts for various engine models. Spark plug gap is documented at 0.040 in. (1.0 mm) for specific serial ranges, while gear case oil capacity is uniformly specified at 28.0 fl. oz. (828 ml). Cylinder head compression readings are provided at 90–110 psi for a warm engine with throttle wide open. The manual details torque values for essential fasteners, such as the 55 lb. ft. (74.5 N·m) specification for propeller nuts and 125 lb. ft. (169.5 N·m) for the flywheel nut. Electrical systems are supported by detailed Ohm tests for components like the crank position sensor, listed at 1100 ±200 ohms. A complete factory-standard 639-page technical manual covering the 1997 Mercury 225 EFI, 250 EFI, 3.0 Litre Marathon, and 3.0 Litre SeaPro, providing engine, chassis, and electrical system specifications for the 0D280813-and-up build.