Heat Exchanger; Raw Water Pump; Exhaust Elbow; Generator Ends - Northern Lights M844W3 Operator's Manual

SP-14. HEAT EXCHANGER
1. Clean the heat exchanger core every 24 months, or
after 2500 hours of operation, or as needed.
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.
SP-15. RAW WATER PUMP
1. Change the seawater pump impeller every 500 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.
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.
SP-16. EXHAUST ELBOW
1. Visually inspect the exhaust elbow every 500 hours
of operation, or sooner if needed. If any rust or other
damage is noted, replace the elbow.
Updated 5-13-21
Servicing

GENERATOR ENDS

The maintenance and operation recommendations for
the generator end are can be found in Owner's Manual
OPX300K-2, included with your manual kit. Contact
your Authorized Northern Lights dealer or factory
representative for additional copies.

ELECTRICAL SYSTEM - GENERAL

CAUTION: Excessive non-linear loads can
lead to regulator and/or generator end failures
and should be no greater than 20% of overall
load. Failures caused by excessive non-linear
loads are not warrantable.
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. When welding near the unit, disconnect the AC and
DC voltage 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.
7. A D.C. circuit breaker protects your control panel
and wiring harness. It is located in the side of the
generator junction box.

GLOW PLUGS

1. Each cylinder is supplied with a glow plug which
serves to heat the combustion chamber for starting.
2. To check the glow plugs, measure the resistance
between terminal and engine block, using a high
quality meter. Resistance should be under 1 ohm.
3. Check all glow plugs and replace any that are faulty.
Figure 19: Glow plugs.
OM844W3 5/21
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