Raw Water Pump; Raw Water Intake Strainer - Westerbeke 8.0 KW-60Hz SBEG Operator's Manual

,
COOLING SYSTEM
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 blades 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. The neoprene impeller
has a limited lifetime and must be inspected regularly.
NOTE:
Should a failure occur with the pump
~
internal parts
(seals and bearings), it may be more cost effective to purchase
a new pump and rebuild the original pump as a spare.
Inspectlng/Changing the Raw Water Pump Impeller
Close the raw water intake valve. Remove the pump cover
and, with the proper size impeller tool, carefully pry the
impeller out of the pump (the impeller can be pried out using
a pair of screwdrivers
if an impeller puller is unavailable. Take
care. not
to
tear
the impeller). Install the new impeller and
();.ring.
Move the blades
to
conform to the curved carn plate
and push the impeller into the pumps housing. When
assembling, apply a thin coating of lubricant to the impeller
'and gasket. Open the raw water intake valve.
Run the engine and check for leaks around the pump. Also
check
for water discharge at the stern tube. Absence of water
dow indicates the pump has not primed itself properly.
NOTE:
Never allow the pump to ron dry. Even a short period
of dry rnnning may destroy the impeller.
INSPECT THE a-RING
. ANO IMPELLER. REPLACE
IF THEY SHOW SIGNS
OF WEAR.
THE PIN FITS INTO THE ____ IMI'EL!ER
SLOT IN THE SHAFT. -----...
LIGHTLY GREASE THE
PUMP CHAMBER, a-RING, .
ANO IMPELLER WITH
. GLYCERIN. .
A
CAUTION:
If any of the blades have broken off the
impeller, they must be located 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 sealing washer if necessary.
5. 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
run
hard
aground.
If the engine temperature gauge ever shows a higher than
normal reading, the cause may be that
sil~
leaves or grass
may have been caught up in the strainer, slowing the flow of
raw water through the cooling system.
FILTER
WASHER
TYPICAL RAW WATER INTAKE STRAINER
((]wner Installed)
DRAINING THE RAW WATER COOLING SYSTEM
When freezing temperatures are expected, the cooling system
can be drained by loosening the raw water pump's cover
plate screws. This should allow the water to drain out of the
pump and also drain back to the strainer.
Open the raw water petcocklplug on the heat exchanger to
allow the raw water to drain.
Engines & Generators
15