This comprehensive repair manual provides detailed instructions for servicing Yanmar marine engines, specifically models 4BY-150, 4BY-180, 6BY-220, and 6BY-260. The manual covers a wide range of topics, enabling you to perform repairs, maintenance, and troubleshooting with confidence.

Within the manual, you'll find in-depth information on general engine operation, routine maintenance procedures, engine removal and installation, fuel system components and troubleshooting, lubrication and cooling system intricacies, engine specifications, transmission and drive train components, steering system analysis, shock absorbers, bodywork, intake and exhaust systems, electrical system diagnostics, and advanced troubleshooting techniques.

This manual is your go-to resource for understanding the inner workings of your Yanmar marine engine and ensuring its optimal performance.

The Yanmar 4BY-150, 4BY-180, 6BY-220, and 6BY-260 marine engines are renowned for their reliability, efficiency, and durability, making them a popular choice for a wide range of marine applications. These powerful and versatile engines are designed for both commercial and recreational boats, offering excellent performance and fuel economy.

The 4BY series features a four-cylinder, direct injection, turbocharged engine with a displacement of 4.0 liters. The 6BY series, on the other hand, boasts a six-cylinder layout with a displacement of 6.1 liters. Both series share a common design philosophy, incorporating advanced technology like overhead camshafts, electronic fuel injection, and a robust crankshaft for exceptional performance. These engines are known for their smooth operation and quiet running even under heavy loads. They are also equipped with a robust cooling system and a reliable exhaust system to ensure long-lasting performance.