This service repair manual covers the Yanmar SY Series marine engines, including models 6SY-STP2, 6SY655, and 8SY-STP. Yanmar engines are recognized for their robust engineering and reliability, providing dependable performance for marine applications. This manual is designed to offer comprehensive guidance for the service and repair of these specific engine models, ensuring their continued optimal operation. The purpose of this English-language manual is to provide detailed instructions and technical information essential for maintaining and repairing your Yanmar SY Series marine engine. It includes sections on general service information, periodic maintenance, engine systems, troubleshooting, and more, all presented with easy-to-read text and high-quality diagrams. All pages are printable, making it a practical resource for owners, mechanics, and technicians.