Northern Lights M673L2 Operator's Manual - page 19
OM673L2 08/05
1
Servicing
SP14. cOOLINg SySTEM fLUShINg
1. Flush the cooling system every 1000 hours or every
12 months, whichever comes first.
a. Remove expansion tank cap and drain engine
block.
b. Leave all drains open.
c. Pour clean water into expansion tank until
water coming from drains is free of
discoloration and sediment.
d. Let water drain completely.
e. Close drains and refill with recommended
mixture.
NOTE: Open sea cock before running engine.
2. Coolant Specifications:
Use 50% water / 50% ethylene glycol antifreeze
mix. Antifreeze mixture is recommended as a good
year-round coolant, but not methyl alcohol based
antifreeze because of its low boiling point. Also,
antifreeze with high silicate should not be used as it
could cause silica gelation problems.
. Check hoses and connections and repair any leakage.
SP15. hEAT EXchANgER
1. Clean the heat exchanger core once a year or after
200 hours of operation.
2. Drain expansion tank and heat exchanger.
. Remove heat exchanger end covers and remove
core.
. Clean the inside of exchanger core tubes using
a metal rod. Flush, inspect and clean again if
necessary.
5. Reassemble. Fill the cooling system, start the engine
and check for leaks.
SP16. RAW WATER PUMP
1. Change the seawater pump impeller every 1000
hours, or as needed.
2. Remove the pump end cover. Pry out the impeller
using needle-nose pliers or two screwdrivers.
Be sure you remove all pieces of failed impeller.
NOTE: Place some kind of protection under the
screwdrivers in order not to damage the pump
housing.
. Clean the inside of the housing.
. Press in the new impeller and place the sealing
washers in the outer end of the impeller center if this
has not already been done.
5. Replace the cover using a new gasket or o-ring.
NOTE: Make sure that there is always an extra
impeller and cover gasket in reserve on board.
gENERATOR ENdS
The maintenance and operation recommendations
for the generator end are located on pages 1-22
under the heading “AC Generator”.
ELEcTRIcAL SySTEM - gENERAL
1. Never switch battery switch off or break the circuit
between the alternator and batteries while the engine
is running. Regulator damage can result.
2. Do NOT reverse the polarity of battery cables when
installing the battery.
. When welding on the unit, disconnect the AC and
DC voltage regulator and battery. Isolate the leads.
. Disconnect the battery cables when servicing the
D.C. alternator.
5. Never test with a screwdriver, etc., against any
terminal to see if it emits sparks.
6. Do not polarize the alternator or regulator.
7. A D.C. circuit breaker protects your control panel
and wiring harness. It is located in the side of the
generator junction box.