This document pertains to Yanmar diesel engines, specifically the 3Ym30, 3Ym20, and 2Ym15 series. These water-cooled, in-line diesel engines are designed for reliable operation and feature a naturally aspirated, direct injection combustion system with electric start. The 3Ym30 model offers approximately 1.1 L displacement, the 3Ym20 approximately 1.0 L, and the 2Ym15 approximately 0.7 L, each with distinct bore and stroke dimensions tailored for efficiency and performance.

This comprehensive repair service manual provides essential information for the maintenance and repair of these Yanmar engines. It covers critical procedures and specifications, including lubrication requirements with recommended oil grades and change intervals, filtration details, and coolant type and replacement schedules. The manual is an indispensable resource for owners, technicians, and mechanics, ensuring the longevity and optimal performance of the Yanmar 3Ym30, 3Ym20, and 2Ym15 diesel engines through detailed guidance and technical data.