2
Chapter 5
VENTILATION SYSTEM- DIESEL
With diesel engines
large amounts of
air are required
to perform the
combustion
process. The higher
the revolutions
per minute of the
engine the more air is required to meet the demand.
Since diesels compress the air at a much higher ratio than
similiar gasoline models that require a spark in the process
the chance of explosion or fi re is much lower with diesel
power. Therefore, it is not necessary to force the exhaust
from the sump with a powered ventilation system like the
gas engine.
Diesel engines exhaust large amounts of incoming air by
mixing it through the combustion process and forcing the
air through the engine exhaust system into the water. The
same deck cowlings are used to funnel incoming air for
combustion. The remaining air exits through the cowlings
into the atmosphere.
This “breathing cycle” occurs naturally within the diesel
with more oxygen being required as the throttle speeds
are increased.
As part of diesel maintenance, ensure the cowlings are free
of debris including animal nests such as wasps and birds.
Check and replace the diesel engine air fi lters as required.
Note that the diesel air fi lter can not be cleaned so scrap it
and replace as needed. See your nearest Regal yacht dealer
for fi lter parts.
Also, it is recommended that after a cruise you let the
engines and generator idle under a ‘no load’ condition for
several minutes. Perform a visual check for exhaust and
fl uid leaks in the bilge. Since there is a light gelcoat color
in the bilge bottom it will be easier to spot any fl uid leaks.
Note: “Do not obstruct or modify the ventilation
system”.
CUMMINS® ENGINE BREAK-IN
The Cummins 6.7 litre engine does not require a “break-
in” procedure. For longevity purposes though the engine
should not be run at a full load condition for extended
periods. Various engine load and speed conditions assist
the internal engine parts such as bearings, valves and pis-
ton rings to “seat” properly which will help ensure a lon-
ger engine life.
During the early life of the engine it is a good idea to
check the engine oil more frequently since it is normal
that the engine will use more oil. If engine oil is required
be sure to check the engine manual for proper grade and
viscosity.
Check the maintenance schedule in your engine owner’s
manual and contact your Regal yacht dealer to set up the
fi rst and subsequent maintenance inspections. Normally
the inspections are scheduled according to engine hours
of operation which are displayed on the helm informa-
tion gauges. Never exceed a 12 month period between oil
changes especially with diesel power since sulfur tends to
enter the lubrication system through the fuel combustion
process over a period of time.
Ventilation
Ducting
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