🏷️ Basic Information Identification Make: Mercury Mercruiser Model: #4 Stern Drive Units MCM 120-260 Year: 1978-1982 Generation: MCM 120-260 Series 📋 Manual Details Documentation Manual Type: Service Repair Manual Language: English Page Count: 230 Format: PDF Downloadable: Yes Compatibility: Windows & Mac Requirements: Adobe PDF Reader ⚙️ Engine Specifications Engine Family Engine Type: Various Inline and V-configuration engines (details depend on specific MCM model) Displacement: Varies by specific MCM engine model (e.g., 260 HP likely a 350 cubic inch V8) Power: 120 HP to 260 HP 🔧 Transmission Drive Unit Ratios Drive Unit Ratios: 1.98:1, 1.84:1, 1.65:1, 1.50:1 Gear Housing Assembly: Included in service manual 🔧 Maintenance Service Procedures Troubleshooting: Covered in manual Disassembly Assembly: Detailed step-by-step instructions Inspection Adjustment: Included in manual Service Bulletins: Included in manual 📄 Components Drive Unit Parts Drive Shaft Housing Assembly: Covered in manual Transom Plate Assembly: Covered in manual Power Trim: Covered in manual Power Steering: Covered in manual 📄 Applications Vehicle Types Boat Motors: MerCruiser Sterndrives and Inboards Specific Models Transom Assemblies: MCM 120/140/165/470/485/898/228/260 (S/N : 4891650 - 6216686) Stern Drive Units: MC 120 - 260 STERN DRIVE UNITS