OM864W 10/18
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SP-15. HEAT EXCHANGER
1. Clean the heat exchanger core once a year or after
2400 hours of operation.
2. Drain the expansion tank and heat exchanger.
3. Remove the heat exchanger end covers.
4. Clean the inside of the exchanger core tubes using
a metal rod. Flush, inspect, and clean again if
necessary.
5. Reassemble the heat exchanger. Fill the cooling
system. Start the engine and check for leaks.
SP-16. RAW WATER PUMP
1. Change the raw water pump impeller every 750
hours, or as needed.
2. Remove the pump cover. Pry out the impeller using
needle-nose pliers or two screwdrivers. Be sure to
remove all pieces of the failed impeller.
NOTE: Place some kind of protection under the
screwdrivers in order to not damage the
pump housing.
3. Clean the inside of the housing.
4. Press in the new impeller and place the sealing plug
in the outer end of the impeller center if this has not
already been done.
NOTE: Make sure that there is always an extra
impeller and cover gasket in reserve on
board.
SP-17. ZINC ELECTRODES
1. A zinc electrode is installed in the heat exchanger
cooling system to protect the engine from electroly-
sis. Check it faithfully every 200 hours. If you are
in warm saltwater, or where electrolysis is a known
problem, check it more often.
2. Remove the zinc holder from the bottom of the
exchanger (
Figure 2-12
). This will drain raw water
from the exchanger.
3. Scrape or steel brush the zinc electrode clean. If
more than 50% of the electrode is corroded away,
replace it with a new zinc. The electrode screws out
of the holder.
4. Reinstall the zinc holders. Be sure the threads are
clean for good metal-to-metal contact. Do not use
thread sealant.
5. Refill the cooling system. Start the engine and check
for leaks.
PTO
Check the manufacturer’s manual for servicing
requirements for the Optional PTO with electric clutch.
Figure 15:
Optional PTO with electic clutch
Servicing
