Yanmar 3JH4BE Service Manual page 3

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
servicing.
Use this manual as a handy reference in daily inspection and maintenance, and as a text for engineering
guidance.
Model 3JH4E has been used for the illustrations in this service manual, but they apply to other models in
the JH4 series engines.
California
Proposition 65 Warning
Diesel engine exhaust and some of its
constituents are known to the State of
California to cause cancer, birth de-
fects, and other reproductive harm.
The contents of this service manual may not be copied or
reproduced without permission.
FOREWORD
California
Proposition 65 Warning
Battery posts, terminals, and related ac-
cessories contain lead and lead com-
pounds, chemicals known to the State
of California to cause cancer and repro-
ductive harm.
Wash hands, after handling.