Installation manual
COOLING
SYSTEM
RAW
WATER
COOLING
CIRCUIT
The raw water flow is created by a positive displacement
impeller pump. This pump draws water directly from the raw
water source (ocean, lake,
or
river) through a hose to the
water strainer.
The
raw water passes from the strainer
through the raw water pump to the heat exchanger (through
the heat exchanger tubes) where it cools the engine circulat-
ing fresh water coolant. The raw water is then discharged
into the water-injected exhaust elbow, mixing with and cool-
ing the exhaust gasses. This mixture
of
exhaust gas and raw
water
is
discharged overboard by the engine's exhaust gas
discharge pressure.
Raw
Water
Pump
The raw water
pump
is a self-priming, rotary pump with a
non-ferrous housing and a neoprene impeller. The impeller
has flexible vanes which wipe against a curved cam plate
within the impeller housing, producing the pumping action.
On no account should this pump be run dry as water acts
as
a
lubricant for the impeller. There should always be a spare
impeller and impeller cover gasket (an impeller kit) aboard.
Raw water pump impeller failures occur when lubricant (raw
water)
is
not present during engine operation. Such failures
are not warrantable, and operators are cautioned to make sure
raw water flow is present at start-up.
NOTE:
Should a failure occur with the
pump's
internal parts
(seals and bearings). it
may be more cost efficient to pur-
chase a new
pump
and
rebuild the original pump
as
a spare.
IMPELLER
INSPECTION:
CHECK
AT
THE
BASE
OF
EACH
BLAOE
BY
BENDING
VIGOROUSLY.
REPLACE
THE
IMPELLER
IF
THERE
ARE
ANY
CRACKS.
WHEN
INSTALLING:
TAKE
CARE
TO
ALIGN
THE
IMPELLER
KEYWAY
WITH
THE
SHAFT
KEY.
FOLD
THE
IMPELLER
BLADES
IN
EITHER
DIRECTION
(THEY
WILL
TURN
IN
THE
CORRECT
POSITION
WHEN
THE
PUMP
STARTS).
GREASE
THE
BLADES
AND
THE
PUMP
CHAMBER
WITH
PETROLEUM
JELLY
TO
PROVIDE
LUBRICATION
FOR
THE
FEW
SECONDS
THE
PUMP
HAS
TO
RUN
DRY.
THE
GREASE
IMPROVES
THE
SEAL
OF
THE
BLADES
AND
MAKES
INSTALLATION
EASIER.
THE
O-RING
GASKET
ONLY
NEEDS
TO
BE
.
REPLACED
IF
IT
SHOWS
..
SIGNS
OF
WEAR.
Changing
the
Raw
Water
Pump
Impeller
Close the raw water intake valve. Remove the pump cover
and, with the aid
of
an
impeller puller, carefully pry the
impeller out
of
the pump. Install the new impeller and gasket.
Move the blades to conform to the curved cam plate and
push the impeller into the pump's housing. When assem-
bling, apply a thin coating
of
lubricant to the impeller and
gasket.
Open the
raw
water intake valve.
To
be certain the pump
is
operating properly, run the engine
and check the following:
o Inspect the raw water pump for leaks.
o After warm up, monitor the temperature gauge. It should
indicate a normal engine temperature.
o Check aft. There should be a steady flow
of
water from
the stem tube.
A
CAUTION:
If
any
of
the
vanes
have
broken
off
the
impeller,
they
must
be
found
to
prevent
blockage
in
the
cooling
circuit.
They
onen
can
be
found
in
the
heat
exchanger.
Impeller
Puller
WESTERBEKE recommends using an impeller puller to
remove the impeller, this will prevent damage to the blades
and to the edges
of
the pump housing.
WATER
LEAKING
HERE
WOULD
INDICATE
THE
PUMP
SEAL
HAS
FAILED
AND
THE
PUMP
NEEDS
IMMEDIATE
SERVICE.
~~~ft-*""---HOUSING
RAW
WATER
PUMP
Engines & Generators
16