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Northern Lights 844W2 / 844LW2 Engine

The Northern Lights 844W2 / 844LW2 is a 4-cylinder engine. It powers generator sets from Northern Lights, including the M20C. It holds 8.2 L (2.2 gal) of oil.

Also known as: 844W2 / 844LW2, Northern Lights 844W2 / 844LW2

Cylinders

8.2 L

Oil capacity

On this pageSpecs Generator sets Maintenance FAQ Service intervals Torque & specs Fluids Procedures Wiring

Engine specifications

Oil capacity	8.2 L
Cylinders	4

Generator sets powered by this engine

Northern Lights M20C

How to read your Northern Lights engine serial & model number →

Common problems

Lack of engine power
Cause: Engine overloaded
Fix: Reduce load
Engine hard to start or will not start
Cause: Improper starting procedure
Fix: See starting section of this manual. Take special note of Bypass Switch operation
Starter cranks slowly
Cause: Low battery output: Batteries too small; Battery cables too small
Fix: Check specific gravity of each battery; Replace battery if necessary
Engine Overheats
Cause: Low coolant level
Fix: Fill tank or radiator to proper level, with proper mixture of coolant; Check hoses for loose connections and leaks.
Engine runs irregularly or stalls frequently
Cause: Below normal engine temperature
Fix: Remove and check thermostat
High Fuel Consumption
Cause: Improper type of fuel
Fix: Use correct fuel for temperature.
Engine Malfunctions at High Output Range
Cause: Fuel supply insufficient
Fix: Air in fuel system or clogged fuel filter element.
Engine Emits Black or Gray Exhaust Smoke
Cause: Clogged or dirty air cleaner
Fix: Service air cleaner.
Starter inoperative
Cause: Check DC circuit breaker
Fix: If the breaker is tripped, reset it
Entire electrical system does not function
Cause: Check DC circuit breaker
Fix: If breaker is tripped, reset it
Engine Knocks
Cause: Insufficient oil
Fix: Call your dealer.
Engine Emits White Smoke
Cause: Improper fuel
Fix: Use correct fuel for temperature.
Low Oil Pressure
Cause: Low oil level
Fix: Fill crankcase to proper level.
High Oil Consumption
Cause: Break-in period
Fix: Oil consumption decreases after break in.
Battery will not charge
Cause: Loose or corroded connections
Fix: Clean and tighten battery connections

Compiled from service & troubleshooting documentation across every generator set that uses the Northern Lights 844W2 / 844LW2.

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter	Marine sets: wash element in soapy water, rinse and dry; replace if necessary		24-23100	1000 hr	Amazon eBay FridayParts $193.84
Fuel filter			24-52020	500 hr	Amazon eBay $24.71 NAPA $15.34
Oil filter			24-03100	250 hr	Amazon eBay $23.45 NAPA $12.88
Belt	Depress about 3/16 in. (5 mm) at midpoint between crankshaft and alternator pulleys		—
Coolant	50% distilled water / 50% ethylene glycol antifreeze mix		—	2500 hr
Oil	API Service CC/CD/CE single viscosity oils; API Service CC/CD/SF multi-viscosity oils	8.2 liters	—	250 hr

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
Battery electrolyte	Check	50 hr		First service — After first 50 hours and every 50 hours (SP18)
Cylinder head bolts	Adjust	50 hr		First service — Re-tighten head bolts after first 50 hours (see pg. 14)
Engine oil	Change	250 hr		First service — After first 50 hours
V-belt tension	Check	50 hr		First service — After first 50 hours (SP5)
Valve clearances	Adjust	50 hr		First service — After first 50 hours
Valves	Adjust	50 hr		First service — SP6 - After first 50 hours
Radiator (industrial only)	Clean	100 hr		EVERY 100 HOURS (SP16); check and clean radiator fins
Primary fuel filter element	Change	200 hr		EVERY 200 HOURS (SP8)
Air cleaner	Check	250 hr		SP4; more often in dusty conditions
Batteries	Check	250 hr		SP19 - Check state of charge of batteries with hydrometer
Batteries	Test	250 hr		Check condition of batteries with hydrometer
Batteries state of charge	Check	600 hr		Hydrometer check (SP19)
Engine oil and filter	Change	250 hr		First service — SP2/SP3 - Every 250 hours
Lube oil filters	Change	250 hr		First service — SP3; also at 100 hours then every 250 hours
Exhaust elbow	Inspect	500 hr		SP22 - Inspect condition
Primary fuel filter element (Racor)	Change	500 hr		SP8; as often as necessary
Secondary fuel filter	Change	500 hr		SP9 - Every 500 hours
Cooling system	Clean	600 hr	12 mo	EVERY 600 HOURS or every 12 months, whichever comes first; check and flush (SP14)
Impeller (seawater pump, marine)	Change	600 hr		EVERY 600 HOURS or as needed (SP17)
Air cleaner element	Change	1000 hr		SP4
Impeller in raw water pump	Change	1000 hr		SP17; or as needed
Injectors	Check	1000 hr		SP11 - Check every 1000 hours by dealer
Raw water pump impeller	Change	1000 hr		SP17 - Every 1000 hours or as needed
Valve clearances	Check	1000 hr		SP6 - Every 1000 hours
Injection nozzles	Clean	1500 hr
Heat exchanger (marine only)	Clean	2400 hr		EVERY 2400 HOURS; also once a year (SP15)
Cooling system	Check	2500 hr		SP14; check and flush
Cooling system	Other	2500 hr	12 mo	SP14 - Check and flush cooling system; every 2500 hours or 12 months
Fuel injection pump	Check	2500 hr		SP12 - Pump settings, max/idle speed and exhaust smoke
Heat exchanger	Clean	2500 hr	12 mo	SP15; or once a year

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

Type	Item	Value	Unit	Condition
Clearance	Heat rejection to jacket coolant (M844K2)	1018	BTU/min	60 Hz
Clearance	Heat rejection to jacket coolant (M844LK2)	1273	BTU/min	60 Hz
Clearance	V-belt deflection	3/16	in	at midpoint between crankshaft and alternator pulleys
Gap	V-belt tension (deflection at midpoint between crankshaft and alternator pulleys)	3/16	in. (5 mm)	thumb pressure
Gap	V-belt tension (deflection at midpoint between crankshaft and alternator pulleys)	about 3/16	in. (5 mm)
Other	Exhaust Gas Temperature	1022	°F (550° C)
Other	Maximum Exhaust Backpressure	48	in (1219 mm) H2O
Other	V-belt deflection	3/16 in. (5 mm)	in. (mm)	thumb pressure at midpoint between crankshaft and alternator pulleys
Pressure	Coolant filler cap pressure valve release	7	PSI (0.5 bar)
Pressure	Coolant filler cap pressure valve release	approximately 7	PSI (0.5 bar)
Pressure	Coolant filler cap release pressure	approximately 7 PSI (0.5 bar)	PSI (bar)
Pressure	Coolant filler cap relief valve	7	PSI
Pressure	Engine oil pressure	above 15 PSI; normal reading 20-60 PSI	PSI	engine running, gauges monitored often
Pressure	Engine oil pressure (normal operating, Series 3-4 panels)	20-60	PSI	after a few seconds of operation
Pressure	Minimum oil pressure	15	PSI	must be above 15 PSI while running
Pressure	Oil pressure	20 - 60	PSI	Normal reading after a few seconds of operation
Pressure	Oil pressure (minimum)	above 15	PSI	Series 3 and Series 4 Control Panels while operating
Pressure	Oil pressure (minimum, operating)	above 15	PSI
Pressure	Oil pressure (normal)	20 - 60	PSI
Pressure	Oil pressure shutdown	14.2	psi (1.0 Kg/ccm)
Pressure	Recommended pressure cap	12.7	psi (0.9 kg/ccm)
Speed	Rated RPM / Frequency	1500 / 50Hz	RPM / Hz
Speed	Rated RPM / Frequency	1800 / 60Hz	RPM / Hz
Temperature	Engine coolant temperature (marine)	below 200	°F
Temperature	Maximum coolant temperature	230	degrees F (110 degrees C)
Temperature	Normal coolant temperature	167° to 194°F (75°C to 90°C)	°F (°C)	normal operation
Temperature	Shutdown temperature (marine)	above 205	°F
Temperature	Standard thermostat modulating range	179-194	degrees F (82-90 degrees C)
Temperature	Water temperature gauge	below 200	°F (94°C)	Marine sets, operating
Temperature	Water temperature gauge (normal / shut off above)	200 / 205	°F (94 / 97°C)	must be below 200°F (94°C)
Temperature	Water temperature gauge limit (marine)	below 200°F (94°C)	°F (°C)	normal operation
Temperature	Water temperature shutdown	above 205	°F (96°C)	Marine units
Temperature	Water temperature shutdown limit (marine)	above 205°F (96°C)	°F (°C)	shut off engine immediately
Torque	Cylinder head bolts	65.1-68.7	ft/lbs (9.0-9.5 kg/m)	cold; tighten in 2 passes, final pass at specified torque
Torque	Delivery lines at injectors	11 - 18	ft./lbs
Torque	Delivery lines at injectors	11-18	ft./lbs
Torque	Delivery lines at injectors	11-18 ft./lbs.	ft/lbs
Torque	Fuel injector	44-51	ft/lbs (6 to 7 Kgm)
Torque	Injector	44 - 51	ft/lbs (6 to 7 kgm)
Torque	Injector	44 - 51 ft/lbs (6 to 7 kgm)	ft/lbs (kgm)
Torque	Injector return line retaining bolts	22-30	ft/lbs
Torque	Return line retaining bolts	22 - 30	ft/lbs
Torque	Return line retaining bolts	22 - 30 ft/lbs	ft/lbs
Torque	Rocker arm cover nuts	5 - 8	ft/lbs (0.8 - 2.3 kg/m)
Torque	Rocker arm cover nuts	5 - 8 ft/lbs (0.8 - 2.3 kg/m)	ft/lbs (kg/m)
Valve clearance	Intake and exhaust valve clearance	0.008	in. (0.2 mm)	cold, engine NOT running, after head bolts retightened
Valve clearance	Intake and exhaust valve clearance	0.008 in. (0.2 mm)	in. (mm)	engine cold, NOT running
Valve clearance	Intake and exhaust valves	0.008	in. (0.2 mm)	Engine cold and NOT running
Valve clearance	Valve clearance (intake and exhaust, rocker arm to valve guide)	0.008	in	cold, engine NOT running
Voltage	D.C. voltmeter reading	11 - 15	volts	at 80°F (25°C) ambient temperature
Voltage	D.C. voltmeter reading	11-15	volts	at 80°F (25°C) ambient temperature
Voltage	D.C. voltmeter reading	between 11 and 15 volts	VDC	at 80°F (25°C) ambient temperature

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

Fluid	Grade	Standard	Ambient	Capacity	Notes
Coolant	50% distilled water / 50% ethylene glycol antifreeze mix				Antifreeze mixture recommended as a good year-round coolant
Coolant	50% water / 50% ethylene glycol antifreeze mix				Recommended as a good year-round coolant
Engine oil	SAE 5-20W	API Service CC/CD/SF multi-viscosity	below -23°C		Below -10°F (-23°C) multi-viscosity; some increase in oil consumption may be expected
Engine oil	SAE 5W	API Service CC/CD/CE or CC/CD/SF	below -23°C		Below -10°F (-23°C). Multi-viscosity alternative SAE 5-20W.
Engine oil	SAE 5W (single viscosity) / SAE 5-20W (multi-viscosity)	API Service CC/CD/CE single viscosity oils; API Service CC/CD/SF multi-viscosity oils	below -23°C		Below -10°F (-23°C); some increase in oil consumption may be expected
Engine oil	SAE 5W single viscosity / SAE 5-20W multi-viscosity	API Service CC/CD/CE single viscosity oils; API Service CC/CD/SF multi-viscosity oils	below -23°C		Below -10°F (-23°C); use Service CC 30 weight oil during the first 100 hours
Engine oil	SAE-5W	API Service CC/CD/CE single viscosity	below -23°C		Below -10°F (-23°C) single viscosity
Engine oil	SAE 10-30W	API Service CC/CD/SF multi-viscosity	-23°C to 0°C		-10 to 32°F (-23 to 0°C) multi-viscosity
Engine oil	SAE 10W	API Service CC/CD/CE or CC/CD/SF	-23°C to 0°C		-10 to 32°F (-23 to 0°C). Multi-viscosity alternative SAE 10-30W.
Engine oil	SAE 10W (single viscosity) / SAE 10-30W (multi-viscosity)	API Service CC/CD/CE single viscosity oils; API Service CC/CD/SF multi-viscosity oils	-23°C to 0°C		-10 to 32°F (-23 to 0°C)
Engine oil	SAE 10W single viscosity / SAE 10-30W multi-viscosity	API Service CC/CD/CE single viscosity oils; API Service CC/CD/SF multi-viscosity oils	-23°C to 0°C		-10 to 32°F (-23 to 0°C)
Engine oil	SAE-10W	API Service CC/CD/CE single viscosity	-23°C to 0°C		-10 to 32°F (-23 to 0°C) single viscosity
Engine oil	SAE 15-40W	API Service CC/CD/SF multi-viscosity	above 0°C		Above 32°F (0°C) multi-viscosity
Engine oil	SAE 30W	API Service CC/CD/CE (single viscosity) or CC/CD/SF (multi-viscosity)	above 0°C	8.2 liter	Above 32°F (0°C). Multi-viscosity alternative SAE 15-40W. Crankcase capacity including oil filter 2.1 gal (8.2 liter) for 844k/844Lk.
Engine oil	SAE 30W (single viscosity) / SAE 15-40W (multi-viscosity)	API Service CC/CD/CE single viscosity oils; API Service CC/CD/SF multi-viscosity oils	above 0°C		Above 32°F (0°C)
Engine oil	SAE 30W single viscosity / SAE 15-40W multi-viscosity	API Service CC/CD/CE single viscosity oils; API Service CC/CD/SF multi-viscosity oils	above 0°C	8.2 liters	Above 32°F (0°C)
Engine oil	SAE-30W	API Service CC/CD/CE single viscosity	above 0°C	2.1 gal (8.2 liters)	Above 32°F (0°C) single viscosity
Fuel	Grade No. 1 diesel	ASTM D975	below 0°C		Use below freezing and for all temperatures above 5,500 ft (1500 m)
Fuel	Grade No. 2 diesel above freezing 32°F (0°C); Grade No. 1 below freezing and above 5,500 ft. (1500 meters)	ASTM designation D975 for diesel fuels; cetane number minimum of 45; sulphur less than 1% (preferably less than 0.5%)			Do not use domestic heating oils, Class B engine, Class D domestic fuels, Class E/F/G/H industrial or marine fuels, ASTM-D975-60T No. 4-D and higher number fuels
Fuel	No. 1 diesel	ASTM D975	below 0°C		Below freezing and for all temperatures at an altitude above 5,500 ft (1500 m).
Fuel	Grade No. 2 diesel	ASTM D975	above 0°C		Use above freezing 32°F (0°C); cetane minimum 45; sulphur less than 1% (preferably less than 0.5%)
Fuel	Grade No. 2 diesel above freezing; Grade No. 1 below freezing and at altitudes above 5,500 ft. (1500 meters)	ASTM designation D975; sulphur less than 1% (preferably less than 0.5%); cetane number minimum of 45	above 0°C		Do not use domestic heating oils, Class B, Class D, Class E/F/G/H industrial or marine fuels, or ASTM-D975-60T No. 4-D and higher
Fuel	No. 2 diesel	ASTM D975	above 0°C		Above freezing 32°F (0°C). Sulphur less than 1% (preferably less than 0.5%); cetane minimum 45.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

Retightening cylinder head bolts adjustment

Tools: Torque wrench

Retighten the head bolts after the first 50 hours.
Tighten bolts when the engine is cold.
Loosen the valve cover and remove the rocker arm cover.
Tighten head bolts with a torque wrench in the sequence shown, evenly in 1 or 2 passes.
Tighten to specified torque in final pass.

SP6 Valve Clearances adjustment

⚠ Valve adjustments should be done after the cylinder head bolts have been re-tightened.

Tools: adjustment screw, lock nut wrench

Adjust valve clearance after 1000 hours or as needed; engine must be cold and NOT running.
Turn the engine over by hand until the inlet valve starts to open and exhaust starts to close (valves rocking).
Turn the crankshaft one more full turn; align the top mark of the crank pulley with the top mark of the timing gear case.
Loosen the lock nut and adjust clearance between rocker arm and valve guide with the adjustment screw.
Clearance on both intake and exhaust valves should be 0.008 in. (0.2 mm).
Repeat for each cylinder; each set of valves must be adjusted individually.
Replace the rocker arm cover and tighten cover nuts to 5 - 8 ft/lbs (0.8 - 2.3 kg/m).

Valve Clearance Adjustment adjustment

Tools: Adjustment screw, Lock nut, Wrench

Adjust valve clearance after the first 50 hours of operation and every 1000 hours thereafter.
Valve adjustments should be done after the cylinder head bolts have been re-tightened; engine should be cold and NOT running.
Watch the valves while turning the engine over by hand until the inlet valve starts to open and the exhaust valve starts to close.
Turn the crankshaft one more full turn and adjust the clearance on both valves for this cylinder.
Loosen the lock nut and adjust clearance between the rocker arm and valve guide of both intake and exhaust valves with the adjustment screw.
Clearance on both intake and exhaust valves should be 0.008 in. (0.2 mm).
Repeat steps for each cylinder; each set of valves must be adjusted individually.
Replace the rocker arm cover. Tighten cover nuts to 5 - 8 ft/lbs (0.8 - 2.3 kg/m).

Valve clearance adjustment (SP6) adjustment

Readjust valve clearance after first 50 hours of operation and every 600 hours thereafter.
Valve adjustments should be done after the cylinder head bolts have been retightened.
Engine should be cold and NOT running.
Turn engine by hand until inlet valve starts to open and exhaust valve starts to close.
Turn crankshaft one more full turn and adjust clearance on both valves for this cylinder.
Loosen lock nut and adjust clearance between rocker arm and valve guide with adjustment screw.
Repeat for each cylinder; each set of valves must be adjusted individually.
Replace rocker arm cover.

Check glow plugs diagnostic

Tools: D.C. test bulb

Loosen the current carrying flat wire between the plus-poles of the glow plugs.
Connect a D.C. test bulb between the plus-pole of the battery and the plus-pole of the glow plug.
If the bulb lights up, the glow plug is functioning properly.
Check all glow plugs and replace any faulty ones.

Checking glow plugs diagnostic

Tools: DC test bulb

Loosen the current carrying flat wire between the plus-poles of the glow plugs.
Connect a DC test bulb between the plus-pole of the battery and the plus-pole of the glow plug.
If the bulb lights up, the glow plug is functioning properly.
Check all glow plugs and replace any faulty ones.

Glow Plug Check diagnostic

Tools: D.C. test bulb

Loosen the current carrying flat wire between the plus-poles of the glow plugs.
Connect a D.C. test bulb between the plus-pole of the battery and the plus-pole of the glow plug.
If the bulb lights up, the glow plug is functioning properly.
Check all glow plugs and replace any faulty ones.

Glow Plug Testing diagnostic

Tools: D.C. test bulb

Loosen the current carrying flat wire between the plus-poles of the glow plugs.
Connect a D.C. test bulb between the plus-pole of the battery and the plus-pole of the glow plug.
If the bulb lights up, the glow plug is functioning properly.
Check all glow plugs and replace any faulty ones.

Shutdowns and Alarms diagnostic

⚠ Do not remove the water fill cap of an overheated engine; escaping steam can cause severe burns.

Check the temperature gauge; if above 205°F (96°C) shut off the engine immediately.
Use the Troubleshooting Guide to isolate the cause of the overheat.
Make repairs and restart after the temperature gauge registers below 200°F (94°C).
If shutdown activated with normal temperature, check crankcase oil level.
If oil level is low, fill with recommended oil and restart, watching oil pressure (20-60 PSI).
If oil level is normal, do NOT restart the engine; call your dealer.

Shutdowns and Alarms Response diagnostic

⚠ Do not remove the water fill cap of an overheated engine. Escaping high temperature steam can cause severe burns.

Check the temperature gauge; if above 205°F (96°C), shut off the engine immediately.
Use the Trouble Shooting Guide to isolate the cause of the overheat.
Make repairs. Restart the Marine set after the temperature gauge registers below 200°F (94°C).
Watch the temperature gauge regularly and turn off the unit if temperature rises above 205°F (96°C).
If shutdown is activated and temperature is normal, check the engine crankcase oil level.
If oil level is low, fill with recommended lubricating oil and restart; watch the oil pressure gauge.
If the oil level is normal, DO NOT restart the engine. Call your dealer for assistance.

Air Cleaner Service maintenance

⚠ Make absolutely sure no impurities enter the engine while changing the element.

⚠ Do NOT run the engine with the air cleaner removed.

Inspect air cleaner every 250 hours; in dusty conditions check more often.
Marine sets: if dirty, wash element in soapy water; rinse and dry thoroughly before re-installing. Replace if necessary.
C-Series sets: the element cannot be cleaned; replace it when necessary.

Bleeding the Fuel System maintenance

⚠ Escaping diesel fuel under pressure can penetrate skin causing serious personal injury.

⚠ Use a piece of cardboard or wood, rather than hands, to search for suspected leaks.

⚠ If injured by escaping fuel, see a doctor at once.

Tools: Hand primer, Cardboard or wood

Loosen bleed bolt “A” on top of the filter.
Pump hand primer “B” on fuel lift pump until pure fuel (no bubbles) escapes from bleed bolt “A”. Tighten bleed screw “A”.
Loosen bleed screw “C”. Pump hand primer “B” until pure fuel escapes. Then tighten bleed screw “C”.
If the engine does not start, loosen a fuel line at the injector while cranking until pure fuel escapes; tighten. Do each line one-at-a-time.
After the engine has started, use a piece of cardboard to look for fuel leaks.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Voltage reconnection

Voltage	Phase	Connection	Notes
110/190	3	wye	Optional voltages (Wye) (NL844L)
110/220	1	zig zag	Optional voltage (NL844L)
115/230	1	zig zag	Optional voltage (NL844L)
120/208	3	wye	Standard low voltage (NL844L); also listed in optional voltages (Wye)
120/240			Optional voltages (GEN) (NL844L); standard output 1 phase, 1.0 power factor
120/240	1	zig zag	Optional voltage (NL844L)
127/220	3	wye	Standard low voltage (NL844L); also listed in optional voltages (Wye)
139/240	3	wye	Optional voltages (Wye) (NL844L)
220/380	3	wye	Standard high voltage (NL844L); also listed in optional voltages (Wye)
240/416	3	wye	Optional voltages (Wye) (NL844L)
254/480	3	wye	Optional voltages (Wye) (NL844L)
277/480	3	wye	Standard high voltage (NL844L)

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Common questions

What is the oil capacity of the Northern Lights 844W2 / 844LW2?

The Northern Lights 844W2 / 844LW2 engine has an oil capacity of 8.2 liters.

Which generators use the Northern Lights 844W2 / 844LW2 engine?

The Northern Lights 844W2 / 844LW2 powers 1 generator set(s), including Northern Lights M20C.

How often should you change the oil in the Northern Lights 844W2 / 844LW2?

The Northern Lights 844W2 / 844LW2 oil change interval is every 250 hours.

What is a common problem with the Northern Lights 844W2 / 844LW2 engine?

A commonly reported issue on generators using the Northern Lights 844W2 / 844LW2 is: Lack of engine power. Cause: Engine overloaded. Fix: Reduce load.