Printed in Japan
History of Revision
Service Manual for Marine Diesel Engine
6LY3-ETP / 6LY3-STP / 6LY3-UTP
Outline of correction
New edition: October 2006
• Old edition : M2215-04E151.
• Changed procedure of long
• Changed troubleshooting.
• Added trouble code.
• Added governor and timer
• Changed removing procedure of
fuel injection pump.
• Added ECS.
• Added air heater.
• Added fuse, relay and harness.
3.2.1 & 3.2.2
6.1.3 & 6.1.4
6.5 & 12.1
This service manual has been compiled 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
©2005 YANMAR CO., LTD
All rights reserved. This manual may not be
reproduced or copied, in whole or in part,
without the written permission of YANMAR
1. General ....