This comprehensive Mercury Mercruiser #3 MARINE ENGINES Service Repair Manual covers a range of Mercury Marine 4 Cylinder, GM 4 Cylinder, GM 6 Cylinder, and GM V-8 Cylinder models, encompassing production years from 1978 to 1984. It is your comprehensive resource for thorough repair, maintenance, and rebuild procedures for your Mercury Mercruiser Marine Engines. This manual will guide you through complete tear-down and rebuild processes, providing detailed pictures, part diagrams, torque specifications, maintenance schedules, troubleshooting tips, and much more. The manual is meticulously organized with clear and concise instructions. It features detailed illustrations, diagrams, wiring schematics, and specifications, making it easy to follow each step. All pages are printable, allowing you to take the information you need directly to your garage or workshop. Whether you're a seasoned mechanic or a DIY enthusiast, this manual provides the necessary information to keep your Mercury Mercruiser Marine Engines running smoothly. Within its pages, you'll find in-depth coverage of every aspect of repair and service, built upon a complete disassembly of each machine. This level of detail, coupled with hundreds of photos and illustrations, guides you through every procedure. The manual encompasses a wide range of Mercury Mercruiser #3 MARINE ENGINES models: **MCM 120** - S/N: 4952701 - 6255465 **MCM 120R** - S/N: 6255466- 6853913 **MCM 140** - S/N: 4918570 - 6256954 **MCM 140R** - S/N: 6256955 - 6852269 **MCM 165** - S/N: 4884835 and Above **MCM 470** - S/N: 4886620 - 6218036 **MCM 470R** - S/N: 6218037 - 6902287 **MCM 485** - S/N: 5685394 and Above **MCM 488R** - S/N: 6170297 - 6899057 **MCM 898** - S/N: 4887830- 6218461 **MCM 898R** - S/N: 6218462 - 6899057 **MCM 228** - S/N: 4902305 - 6225266 **MCM 228R** - S/N: 6225267 - 6899268 **MCM 260** - S/N: 4908850- 6227756 **MCM 260R** - S/N: 6227757 - 6890705 **MCM 330** - S/N: 4889680 - 60831 44 **MCM 330 (8-W)** - S/N: 6083145- 6920831 **MCM 370/ 400** - S/N: 4883520- 6721534 **MCM 400 Cyclone** - S/N: 5669232 - 6844266 **MCM 440 Cyclone** - S/N: 6181070 - OA429860 **MCM 460 Cyclone** - S/N: 6180970-6181039 **MCM 475 Turbo** - S/N: 5670797 and Below **MCM 470TR** - S/N: All (Note 1) **MCM 230TR** - S/N: 6901029 and Below (Note 1) **MCM 260TR** - S/N: 6885891 and Below (Note 1) **MIE 470** - S/N: All **MIE 228** - S/N: 4931100 - 5907057 **MIE 230** - S/N: 5907058 - 6901 029 **MIE 255** - S/N: 4924565 - 5907057 **MIE 260** - S/N: 5907058- 6885891 **MIE 330** - S/N: 4890180 - 5889913 **MIE 340** - S/N: 5889914- OA307952 **Note 1:** Refer to the appropriate "Stern Drive Service Manual" for Transom Assembly and Stern Drive Unit Repair. The manual's content is organized into distinct sections, each dedicated to a specific aspect of your engine: **1 - IMPORTANT INFORMATION / TROUBLESHOOTING** * General Information * Maintenance * Troubleshooting **2 - REMOVAL-INSTALLATION-ALIGNMENT** * MCM 120 / 140 / 165 * MCM 120R / 140R Driveshaft Extension Models * MCM 470 / 485 / 488 * MCM 898 / 228 / 260 * MCM 898 / 228 / 260 Driveshaft Extension Models * MCM 330TR / TRS with Mercury Marine Transmission * MCM 330 (B-W) TR / TRS * MCM 370 / 400TRS and Hi-Performance Engines * MIE 470 / 228 / 230 / 255 / 260 / 330 / 340 **3 - ELECTRICAL SYSTEM** * Starting System * Ignition System * Charging System * Instrumentations * Electrical Kits * Wiring Diagrams **4 - FUEL SYSTEMS** * Fuel Delivery System and Fuel Pumps * Rochester 2 Barrel * MerCarb 2 Barrel * Rochester 4 Barrel * Holley 4 Barrel **5 - EXHAUST SYSTEM** * Exhaust Manifolds/ Elbows * Exhaust Risers * Exhaust Collectors **6 - ENGINE** * GM In-Line * Mercury Marine 4 Cylinder Engine * GM V-8 **7 - COOLING SYSTEM** * Seawater Cooled Models * 470 / 485 / 488 * Closed Cooled Models **8 - DRIVE SYSTEMS** * Velvet Drive (Borg-Warner) Transmission * Mercury Marine Transmission * Driveshaft Models / Propeller Shaft **9 - POWER STEERING SYSTEM**

The Mercury Mercruiser #3 marine engines, produced by Mercury Marine from 1978 to 1984, represent a significant era in recreational boating. These engines, utilizing General Motors technology, were offered in a variety of configurations, encompassing 4-cylinder, 6-cylinder, and V-8 engine options. This diversity allowed Mercury Mercruiser to cater to a wide range of boating needs, from smaller, more economical vessels to larger, performance-oriented craft. The Mercruiser #3 engines were renowned for their reliability and durability, a testament to the engineering expertise of both Mercury Marine and General Motors. Their robust construction and proven design allowed them to withstand the rigors of marine environments, providing years of dependable operation for boaters. The Mercury Mercruiser #3 engines were characterized by their versatility and adaptability. The 4-cylinder engines, with their compact size and fuel efficiency, were ideal for smaller boats and personal watercraft. The 6-cylinder engines, offering a balance of power and economy, were well-suited for larger displacement boats and cruisers. The V-8 engines, with their impressive power output and torque, were preferred for high-performance boats and sport fishing vessels. The Mercruiser #3 engines were also known for their ease of maintenance, making them a popular choice for both novice and experienced boaters. The combination of power, reliability, and user-friendliness solidified the Mercruiser #3 engines as a staple in the marine industry during their production years.