22
OL944D 11/13
SP16. HEAT EXCHANGER
1. Clean the heat exchanger core once a year or after
2000 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.
SP17. RAW WATER PUMP
1. Change the raw water pump impeller every 500
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.
SP18. ZINC ANODES
1. A zinc anode is installed in the heat exchanger
cooling system to protect the engine from
electrolysis. Check it faithfully every 250 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. This will drain raw water from the
exchanger.
3. Scrape or wire brush the zinc anode clean. If more
than 50% of the anode is corroded away, replace
it with a new zinc. The anode 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. Start the engine and check for leaks.
Servicing
