This workshop service repair manual covers the Yanmar 3YM30, 3YM20, and 2YM15 marine diesel engines. Engineered for reliability and performance, these engines are designed to meet the demanding requirements of marine applications. While specific production years are not detailed, this comprehensive guide ensures you have the necessary information to maintain and operate your Yanmar engine effectively, regardless of its age. This manual provides complete A-Z coverage for all service and repair procedures, offering step-by-step instructions accompanied by illustrations to facilitate understanding. It is designed to assist owners, mechanics, and technicians in performing routine maintenance, troubleshooting issues, and executing repairs. The manual's detailed content, including technical specifications and maintenance schedules, empowers users to keep their Yanmar engines in optimal working condition, promoting longevity and cost savings through DIY maintenance.