Cooling System Flushing; Heat Exchanger; Raw Water Pump; Generator Ends - Northern Lights Lugger M843NW3 Operator's Manual

Servicing
SP14. COOLINg SySTEM fLUShINg
1. Flush the cooling system every 600 hours or every
12 months, whichever comes first.
2. Marine sets:
a. Remove expansion tank cap and drain engine
block.
b. Open block drain cock. Remove hose from
bottom of heat exchanger tank.
c. Pour clean water into expansion tank until water
coming from drains is free of discoloration and
sediment. Let water drain completely. Close
drains and refill with recommended mixture.
3. Coolant Specifications:
Use 50% distilled water / 50% ethylene glycol anti-
freeze mix. Antifreeze mixture is recommended as a
good year-round coolant.
4. Check hoses and connections and repair any leakage.
SP15. hEAT EXChANgER
1. Clean the heat exchanger core once a year or after
2400 hours of operation.
2. Drain expansion tank and heat exchanger.
3. Remove heat exchanger end covers and remove
core.
4. 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.
SP17. 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. If the impeller has broken into pieces,
remove front heat exchanger end cover and inspect
for impeller pieces. Clean inlet to heat exchanger
bundle and reassemble.
3. Clean the inside of the housing.
4. 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.
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 in a separate Owner's
Manual. If you do not have one of these manuals,
contact your local Northern Lights dealer.

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.
3. If welding on the unit, disconnect the regulator and
battery. Isolate the leads.
4. 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.
OM843NW3 01/08
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