Printed in Japan
History of Revision
Service Manual for Marine Diesel Engine
Outline of correction
New edition March 2004
Add : Eug.
1. Specifications table added.
2. Engine outline added.
3. Piping diagram added.
4. Other data added.
1. Front cover added to engine
2. Notice on seawater pump
rotating direction was changed.
3. Incorrect word corrected.
1. Engine mounting bolt side pitch
(3YM30 with KM2P-1).
2. Engine mounting bolt side pitch
(3YM30C with SD20).
3. No-load max. speed (3YM20).
This service manual has been complied for engineers engaged in sales, service, inspection and
maintenance. Accordingly, descriptions of the construction and functions of the engine are emphasized
in this manual, while items, which should already be common knowledge, are omitted.
One characteristic of a marine diesel engine is that its performance in a vessel is governed by the
applicability of the vessel's hull construction and its steering system.
Engine installation, fitting out and propeller selection have a substantial effect on the performance of the
engine and the vessel. Moreover, when the engine runs unevenly or when trouble occurs, it is essential
to check a wide range of operating conditions - such as installation to the full and suitability of the ship's
piping and propeller - and not just the engine itself. To get maximum performance from this engine, you
should completely understand its functions, construction and capabilities, as well as proper use and
Use this manual as a handy reference in daily inspection and maintenance, and as a text for engineering
Model 3YM30 has been used for the illus