🏷️ Basic Information Identification Make: Mercury Mercruiser Model: Mercruiser #4 Stern Drive Units MCM 120-260 Model Variant: MCM 120/140/165/470/485/898/228/260 Production Years: 1978-1982 Generation: 4th Generation Stern Drive 📋 Manual Details Documentation Manual Type: Service Repair Manual Language: English Page Count: 230 Format: PDF Features Printable: True Searchable: True Illustrations: Detailed Diagrams: Exploded Views, Wiring Schematics Compatibility: Windows, Mac, iOS, Android ⚙️ Engine Specifications Powerhead Engine Type: Marine Inboard/Outboard (Sterndrive) Engine Displacement Range: Refer to specific MCM model (e.g., 120, 140, 165, 260 HP) Horsepower Range: 120-260 HP 🔧 Transmission Drive Unit Drive Type: Stern Drive (Outdrive) Gear Ratio Options: 1.98:1, 1.84:1, 1.65:1, 1.50:1 🔧 Maintenance General Covered Procedures: Maintenance, Troubleshooting, Rebuild, Refurbish, Restore Diagnostic Coverage: All diagnostic procedures 📄 Technical Data Drive Unit Housing Component Coverage: Drive Shaft Housing Assembly, Gear Housing Assembly Transom Assembly Component Coverage: Transom Plate Assembly Ancillary Systems Component Coverage: Power Trim, Power Steering Specifications Torque Specs: Included Part Information Diagrams: Part Diagrams included 📄 Serial Number Coverage Transom Assemblies Mcm 120/140/165/470/485/898/228/260 Serial Range: 4891650 - 6216686 Stern Drive Units Mc 120-260 1.98:1 Serial Range: 4893635 - 6237860 Mc 120-260 1.84:1 Serial Range: 4893835 - 6225576 Mc 120-260 1.65:1 Serial Range: 4890460 - 6268064 Mc 120-260 1.50:1 Serial Range: 4898730 - 6229157