Westerbeke 12.5 BTDA - Raw Water Pump Impeller Maintenance; Raw Water Intake Strainer Cleaning; Heat Exchanger Operation

COOLING SYSTEM
CHANGING THE RAW WATER PUMP IMPELLER
Close the raw water intake valve. Remove the pump cover
and gasket or 0-rlng With the aid of two screwdrivers or
pliers. Carefully pry/pull the impeller out of the pump.
Lightly coat the inside of the pump housing ~ith glycerine.
Install the new impeller, bending the blades in the direction
of the curve of the cam plate. Re-assemble the gasket and
cover. Open the raw water intake valve. ".
INSPECTION: CHECK fflE BASE OF
EACH BLADE BY BENDING VIGOROUSLY.·
REPLACE THE IMPELLER IF
ANY'CRACKS.
RAW WATER PUMP
A CAUTION: If any of the vanes have broken off the
Impeller, they must be found to prevent blockage In the
cooling circuit.· They often can be found In the heat
exchanger.
Raw Water Intake Strainer
NOTE: Always install the strainer at or below the waterline so
the strainer will always be self-priming.
A clean raw water intake strainer is a vital component of the
engine's cooling system. Include a visual inspection of this
strainer when making your periodic engine check. The water
in 'the glass should be clear.
Perform the following maintenance after every 100 hours of
operation:
1. Close the raw water seacock.
2. Remove and clean the strainer filter.
3. Clean the glass.
4. Replace the washer if necessary.
s. Reassemble and install the strainer.
6. Open the seacock.
7. Run the engine and check for leaks.
:NOTE: Also follow the above procedure after having nm hard
a [/round.
If .the engine temperature gauge ever shows a higher than
norinal reading, the cause may be that silt, leaves or grass
may have been caught up in the strainer, slowing the flow of
raw water through the cooling system.
RAW WATER STRAINER
WASHER
TYPICAL RAW WATER INTAKE STRAINER
(OWNER INSTALLED)
HEAT EXCHANGER
The heat exchanger is a copper cylinder which encloses a
number of small copper tubes. Raw water is pumped through
the small copper tuJ?es and the fresh water coolant from the
engine is circulated around the copper tubes. The raw water
removes heat from the fresh water coolant.
CLEAN
DEBRIS
Ci.EANd.Jr
DEBRIS AT
BOTH ENDS
HEAT EJ{CHANGER$ ARE
AWJAVA/LABLE WITH
CUPRO·NICKEL TUBING
t-w-IWESTERBEICE
l Engines & Generators
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