🏷️ Basic Information Identification Make: Mercury Mariner Model: 25 Bigfoot Engine Type: 4-Stroke Starting Model Year: 1998 Starting Serial Number: 0G590000 Generation: 1998 and Newer Model Variant: Bigfoot 📋 Manual Details Document Info Manual Type: Service Repair Manual Language: English Format: PDF Delivery Method: Instant Download Compatibility: Windows & Mac Required Software: Adobe PDF Reader, WinZip Content Coverage Covered Sections: • Important Information • Electrical • Fuel System • Powerhead • Mid-Section • Lower Unit • Attachments/Control Linkage • Manual Starter • Color Diagrams ⚙️ Engine Specifications Powerhead Engine Configuration: Inline 3-Cylinder Bore: Approx. 3.0 inches (76 mm) Stroke: Approx. 3.2 inches (82 mm) Displacement: Approx. 67.5 cubic inches (1.1 L) Compression Ratio: Approx. 9.0:1 Fuel Type: Unleaded Gasoline Recommended Fuel Octane: 87 Octane (Regular) Ignition System: CDI (Capacitor Discharge Ignition) Spark Plug Type: NGK DCPR6E Spark Plug Gap: 0.030 inches (0.76 mm) 🔧 Transmission Gearcase Gearcase Ratio: 2.33:1 Gear Oil Type: Mercury High Performance Gear Lubricant Gear Oil Capacity: Approx. 14.5 fl oz (430 ml) 🔧 Maintenance Scheduled Maintenance Engine Oil Type: SAE 25W-40 Marine Outboard Oil Engine Oil Capacity: Approx. 4.5 US quarts (4.3 L) Fuel Filter Replacement Interval: Annually or 50 Hours Spark Plug Replacement Interval: Annually or 100 Hours