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Northern Lights O843K Generator Set

The Northern Lights O843K is a generator set.

1
Document types

How to read your Northern Lights serial & model number →

Service parts for the O843K

Grouped by system, with how many of each the parts manual calls for.

Air intake

1 required

Fuel system

1 required

Oil system

1 required

Prices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.

Specifications

AlternatorPX-300K

Maintenance & consumables

ItemSpecCapacityPart #Interval
Air filterAir cleaner element (marine)24-23100 Amazon eBay FridayParts $193.84
Fuel filter130336020200 hr Amazon eBay $24.71
Oil filter24-03100100 hr Amazon eBay $23.45 NAPA $12.88
Battery—600 hr
Belt—100 hr
Coolant—
Oil—50 hr
Spark plug—100 hr

Service intervals

18
ItemActionHoursMonthsNotes
Battery electrolyteCheck50 hr1 moFirst service — After first 50 hours; check every 50 hours or once per month
Cylinder head boltsAdjust50 hrFirst service — Retighten after first 50 hours
V-belt tensionCheck50 hrFirst service — After first 50 hours
ValvesAdjust50 hrFirst service — After first 50 hours
Batteries, cables and terminalsClean100 hrCheck and clean every 100 hours
Radiator finsClean100 hrIndustrial only; clean in very dusty applications
Air cleanerCheck200 hrEvery 200 hours; more often in dusty conditions
Engine oil and filterChange200 hrFirst service — Every 200 hours
Exhaust elbowInspect200 hrEvery 200 hours; check for corrosion and exhaust leakage
Primary fuel filter element (Racor)Change200 hrEvery 200 hours or as necessary
Secondary fuel filterChange200 hrEvery 200 hours
BatteriesTest600 hrCheck condition with hydrometer every 600 hours
Cooling systemClean600 hr12 moFlush every 600 hours or every 12 months, whichever comes first
InjectorsCheck600 hrEvery 600 hours by dealer or injection repair station
Raw water pump impellerReplace600 hrMarine only; every 600 hours or as needed
Valve clearancesCheck600 hrEvery 600 hours
Fuel injection pumpCheck2400 hrEvery 2400 hours
Heat exchangerClean2400 hr12 moMarine only; once a year or after 2400 hours

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

25
TypeItemValueUnitCondition
ClearanceV-belt deflection3/16inmidpoint between crankshaft and alternator pulleys
ClearanceV-belt deflection5mmmidpoint between crankshaft and alternator pulleys
PressureCoolant filler cap pressure valve0.5bar
PressureCoolant filler cap pressure valveapproximately 7PSI
PressureOil pressureabove 15PSIoperating
PressureOil pressure after a few seconds of operation20-60PSInormal reading
TemperatureIndustrial shutdown temperatureabove 110°Cshut off engine immediately
TemperatureIndustrial shutdown temperatureabove 230°Fshut off engine immediately
TemperatureMarine shutdown temperatureabove 205°Fshut off engine immediately
TemperatureMarine shutdown temperatureabove 96°Cshut off engine immediately
TemperatureWater temperature gauge (industrial)below 107°Coperating
TemperatureWater temperature gauge (industrial)below 225°Foperating
TemperatureWater temperature gauge (marine)below 200°Foperating
TemperatureWater temperature gauge (marine)below 94°Coperating
TorqueCylinder head bolts60 - 64ft/lbscold
TorqueCylinder head bolts9.0 - 9.5kg/mcold
TorqueDelivery lines at injectors11-18ft./lbs
TorqueInjector44 - 51ft/lbs
TorqueInjector6 to 7kgm
TorqueReturn line retaining bolts22 - 30ft/lbs
TorqueRocker arm cover nuts0.8 - 2.3kg/m
TorqueRocker arm cover nuts5 - 8ft/lbs
Valve clearanceIntake and exhaust valve clearance0.008incold, engine not running
Valve clearanceIntake and exhaust valve clearance0.2mmcold, engine not running
VoltageDC voltmeter11 - 15volts80°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

FluidGradeStandardAmbientCapacityNotes
Coolant50% distilled water / 50% ethylene glycol antifreeze mix4.1 litersRecommended as a good year-round coolant; approx cooling capacity HE 1.1 gal (4.1 liter)
Engine oilSAE 5-20WAPI Service CC/CD/SF multi-viscositybelow -23°CBelow -10°F (-23°C)
Engine oilSAE 5WAPI Service CC/CD/CE single viscositybelow -23°CBelow -10°F (-23°C)
Engine oilSAE 10-30WAPI Service CC/CD/SF multi-viscosity-23°C to 0°C-10 to 32°F (-23 to 0°C)
Engine oilSAE 10WAPI Service CC/CD/CE single viscosity-23°C to 0°C-10 to 32°F (-23 to 0°C)
Engine oilSAE 15-40WAPI Service CC/CD/SF multi-viscosityabove 0°CAbove 32°F (0°C)
Engine oilSAE 30WAPI Service CC/CD/CE single viscosityabove 0°CAbove 32°F (0°C)
FuelNo. 1 dieselASTM D975below 0°CBelow freezing and all temperatures at altitude above 5,500 ft. (1500 meters)
FuelNo. 2 dieselASTM D975above 0°CAbove 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

12
Valve Clearances adjustment

⚠ Engine should be cold and NOT running.

Tools: Feeler gauge, Wrench

  1. Adjust valve clearance after first 50 hours and every 600 hours thereafter.
  2. Do adjustment after cylinder head bolts have been retightened; engine cold and NOT running.
  3. Turn engine by hand until inlet valve starts to open and exhaust valve starts to close; turn one more full turn.
  4. Loosen lock nut and adjust clearance between rocker arm and valve guide to 0.008 in. (0.2 mm).
  5. Repeat for each cylinder; replace rocker arm cover and tighten cover nuts to 5 - 8 ft/lbs.
Air Cleaner Service maintenance

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

  1. Inspect air cleaner every 200 hours; check more often in dusty conditions.
  2. Marine: if dirty, wash element in soapy water; rinse and dry thoroughly before reinstalling.
  3. Marine: replace element if necessary.
  4. Industrial: element cannot be cleaned; replace when necessary.
  5. Make sure no impurities enter engine while changing element.
Battery Care maintenance

⚠ Battery gas can explode; keep flames and sparks away from batteries.

Tools: Hydrometer

  1. Check electrolyte level every 50 hours or once per month; add distilled water to manufacturer's recommended level.
  2. Check and clean batteries, cables, and terminals every 100 hours.
  3. Clean corrosion with water and baking soda solution; flush with clean water.
  4. Tighten terminals and grease them to inhibit corrosion.
  5. Check battery condition with a hydrometer every 600 hours.
Bleeding the Fuel System maintenance

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

⚠ Use cardboard or wood, not hands, to search for suspected leaks.

Tools: Wrench

  1. Loosen bleed bolt A on top of the filter.
  2. Pump hand primer B on fuel lift pump until pure fuel without bubbles escapes from bleed bolt A; tighten A.
  3. Loosen bleed screw C; pump hand primer B until pure fuel escapes; tighten C.
  4. If engine does not start, loosen a fuel line at the injector while cranking until pure fuel escapes; tighten connection.
  5. After engine starts, use cardboard to look for fuel leaks.
Changing Lube Oil Filter maintenance

⚠ Overtightening can damage the filter housing.

Tools: Filter wrench

  1. Use a filter wrench to remove old filter; discard in approved manner.
  2. Remove and discard old filter gasket; clean mount face.
  3. Spread thin film of engine oil on new filter gasket.
  4. Screw filter on until gasket meets sealing surface.
  5. Tighten one-half turn farther by hand only.
  6. Fill engine with recommended oil; start and check for leakage.
  7. Stop engine, wait 3 minutes, and check oil level; add oil if necessary.
Cooling System Flushing maintenance

⚠ Allow engine to cool before working on cooling system.

⚠ Open filler cap carefully using protective clothing when engine is warm.

  1. Flush cooling system every 600 hours or every 12 months, whichever comes first.
  2. Marine: remove expansion tank cap and drain engine block.
  3. Marine: open block drain cock and remove hose from bottom of heat exchanger tank.
  4. Marine: flush with clean water until drains are free of discoloration and sediment; drain completely and refill with recommended mixture.
  5. Industrial: remove radiator cap and open drain cocks on radiator and engine block.
  6. Industrial: flush until water is clear; drain completely and refill with recommended coolant mixture; clean radiator fins.
  7. Check hoses and connections and repair any leakage.
Engine Oil Change maintenance

⚠ Never use flushing oil or additives in crankcase.

⚠ Dispose of waste oil in an approved manner.

Tools: Oil drain container

  1. Change engine oil and oil filter after first 50 hours; use Service CC 30 weight oil during first 100 hours.
  2. Change oil and filter again at 100 hours; thereafter change every 200 hours.
  3. Warm engine, loosen clamp on oil change tube, remove cap, and drain oil.
  4. Replace cap and tube; refill with recommended oil for the season.
Fuel Filter Replacement maintenance

⚠ Do not overtighten.

Tools: Filter wrench

  1. Remove spin-on filter by turning counterclockwise with a filter wrench.
  2. Fill new cartridge with fuel and apply engine oil to gasket surface.
  3. Screw on until gasket surface contacts sealing surface of filter base.
  4. Tighten two-thirds of a turn by hand; do not overtighten.
Raw Water Pump Impeller Replacement maintenance

⚠ Place protection under screwdrivers so pump housing is not damaged.

⚠ Keep an extra impeller and cover gasket in reserve on board.

Tools: Needle-nose pliers or two screwdrivers

  1. Change seawater pump impeller every 600 hours or as needed.
  2. Remove pump end cover.
  3. Pry out impeller using needle-nose pliers or two screwdrivers.
  4. Remove all pieces of failed impeller and clean inside of housing.
  5. Press in new impeller and place sealing washers in outer end of impeller center.
  6. Replace cover using a new gasket.
Retightening Cylinder Head Bolts maintenance

Tools: Torque wrench

  1. Tighten bolts when the engine is cold.
  2. Loosen nuts and remove rocker arm cover.
  3. Tighten head bolts with a torque wrench in the order shown.
  4. Tighten evenly in 2 or 3 passes, ending at specified torque in final pass.
Winterizing / Out-of-Service maintenance

⚠ Store set in a dry, protected place; if stored outside, protect with a cover.

  1. Marine: drain fresh water and seawater cooling systems completely; shut off seacocks before opening drain cocks.
  2. Marine: drain water supply lines and wet exhaust line; loosen seawater pump cover and drain pump.
  3. Industrial: drain and flush radiator and cooling system; leave dry or refill with antifreeze-water mixture.
  4. Industrial: fill fuel tank or add biocide; seal air cleaner inlet, exhaust opening, crankcase breather pipe, and fuel tank vent.
  5. Marine and industrial: change crankcase oil and filter; loosen alternator belt.
  6. Disconnect and clean battery; remove to warm storage if possible.
  7. Clean outside of unit; paint scratched or chipped surfaces; apply corrosion preventative to exposed metal.
Before Starting operation

⚠ Use protective clothing and open the filler cap carefully when the engine is warm to prevent burns.

⚠ The battery switch must always be kept ON while the engine is running.

  1. Check coolant level about 1 in. (2.5 cm) below filler cap sealing surface when cold.
  2. Check crankcase oil with dipstick; level must be in waffled area.
  3. Check fuel tank level and open any fuel valves.
  4. Marine: close sea-cock; clean sea strainer; reopen sea-cock.
  5. Marine: place battery switch in ON position and keep it ON while running.

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 alternator comes on the Northern Lights O843K?

The Northern Lights O843K uses a PX-300K alternator.

What oil filter does the Northern Lights O843K use?

The Northern Lights O843K uses oil filter part number 24-03100.

What fuel filter does the Northern Lights O843K use?

The Northern Lights O843K uses fuel filter part number 130336020.

What air filter fits the Northern Lights O843K?

The Northern Lights O843K uses air filter part number 24-23100.

Troubleshooting

73

Symptoms & remedies

SymptomCauseRemedy
Battery Will Not ChargeLoose or corroded connectionsClean and tighten battery connections.
Battery Will Not ChargeSulfated or worn out batteriesCheck specific gravity of each battery; Check electrolyte level of each battery.
Battery Will Not ChargeLoose or defective alternator beltAdjust belt tension; Replace belt.
Starter InoperativeCheck DC circuit breakerIf the breaker is tripped, reset it.
Starter InoperativeLoose or corroded connectionsClean and tighten loose battery and harness plug connection.
Starter InoperativeLow battery outputCheck specific gravity of each battery; Check electrolyte level of each battery.
Starter InoperativeDefective electrical system ground wireRepair or replace.
Starter Cranks SlowlyLow battery outputBattery is too small; Battery cables are too small.
Starter Cranks SlowlyCheck specific gravity of each batteryReplace battery if necessary.
Starter Cranks SlowlyCheck electrolyte level of each batteryIf low, fill cells with distilled water.
Starter Cranks SlowlyCrankcase oil too heavyFill with oil of appropriate viscosity.
Starter Cranks SlowlyLoose or corroded connectionsClean and tighten loose connections.
Entire Electrical System Does Not FunctionCheck DC circuit breakerIf breaker is tripped, reset it.
Entire Electrical System Does Not FunctionFaulty connectionClean and tighten battery and harness plug connections.
Entire Electrical System Does Not FunctionSulfated or worn out batteriesCheck specific gravity and electrolyte level of each battery.
Engine Hard to Start or Will Not StartImproper starting procedureSee starting section of this manual. Take special note of Bypass Switch operation.
Engine Hard to Start or Will Not StartNo fuelCheck level of fuel in fuel tank.
Engine Hard to Start or Will Not StartLow battery outputCheck electrolyte level and condition.
Engine Hard to Start or Will Not StartExcessive resistance in starting circuitClean and tighten all battery connections.
Engine Hard to Start or Will Not StartCrankcase oil too heavyUse oil of proper viscosity.
Engine Hard to Start or Will Not StartImproper type of fuelConsult fuel supplier and use proper type of fuel for operating condition.
Engine Hard to Start or Will Not StartWater, dirt or air in fuel systemDrain, flush, fill and bleed system.
Engine Hard to Start or Will Not StartClogged primary fuel filter elementClean or replace filter element.
Engine Hard to Start or Will Not StartClogged secondary fuel filter elementReplace filter element.
Engine Hard to Start or Will Not StartDirty or faulty injection nozzlesHave your dealer check injection nozzles.
Engine Runs Irregularly or Stalls FrequentlyBelow normal engine temperatureRemove and check thermostat.
Engine Runs Irregularly or Stalls FrequentlyClogged primary fuel filter elementClean or replace filter element.
Engine Runs Irregularly or Stalls FrequentlyClogged secondary fuel filter elementReplace secondary filter element.
Engine Runs Irregularly or Stalls FrequentlyWater or dirt in the fuel systemDrain, flush, fill and bleed system.
Engine Runs Irregularly or Stalls FrequentlyDirty or faulty injection nozzlesHave your dealer check injection nozzles.
Engine Runs Irregularly or Stalls FrequentlyAir in fuel systemInspect clamps and hoses on suction side of fuel pump for air leak.
Engine Runs Irregularly or Stalls FrequentlyImproper type of fuelConsult fuel supplier and use proper type of fuel for operating condition.
Lack of Engine PowerIntake air restrictionService air cleaner.
Lack of Engine PowerClogged primary fuel filter elementClean or replace filter element.
Lack of Engine PowerClogged secondary fuel filter elementReplace filter element.
Lack of Engine PowerImproper type of fuelConsult fuel supplier and use proper type of fuel for operating conditions.
Lack of Engine PowerOverheated engineSee "Engine Overheats" in next category.
Lack of Engine PowerBelow normal engine temperatureRemove and check thermostat.
Lack of Engine PowerImproper valve clearanceReset valves. Best done by dealer.
Lack of Engine PowerDirty or faulty injection nozzlesReplace injectors. Best done by dealer; See your local dealer.
Engine OverheatsLow coolant levelFill tank or radiator to proper level; Check hoses for loose connections and leaks.
Engine OverheatsKeel cooling tubes have been painted (marine)Remove paint from tubes.
Engine OverheatsCooling system needs flushingFlush cooling system.
Engine OverheatsDefective thermostatRemove and check thermostat.
Engine OverheatsDefective temperature gaugeCheck water temperature with thermometer and replace gauge if necessary.
Engine OverheatsWater pump impeller worn/brokenCheck impeller and replace if necessary.
Engine KnocksInsufficient oilCall your dealer.
Engine KnocksInjection pump out of timeCall your dealer.
Engine KnocksBelow normal engine temperatureCheck your thermostats; Check water temperature to see if temperature gauge is working properly.
Engine KnocksEngine overheatingSee "Engine Overheating" section.
High Fuel ConsumptionImproper type of fuelUse correct fuel for temperature.
High Fuel ConsumptionClogged or dirty air cleanerService air cleaner.
High Fuel ConsumptionImproper valve clearanceSee your dealer.
High Fuel ConsumptionInjection nozzles dirtySee your dealer.
High Fuel ConsumptionInjection pump out of timeSee your dealer.
High Fuel ConsumptionEngine not at proper temperatureCheck your thermostats; Check water temperature with thermometer and replace gauge if necessary.
Below Normal Engine TemperatureThermostat not working properlyCheck thermostat.
Below Normal Engine TemperatureTemperature gauge not working properlyCheck water temperature with thermometer.
Low Oil PressureLow oil levelFill crankcase to proper level.
Low Oil PressureImproper type of oilDrain and fill crankcase with correct oil.
Low Oil PressurePartially plugged oil filterReplace filter.
High Oil ConsumptionBreak-in periodOil consumption decreases after break in.
High Oil ConsumptionCrankcase oil too lightUse proper viscosity oil.
High Oil ConsumptionOil leaksCheck for leaks in lines around gaskets and drain plug.
Engine Emits Black or Gray Exhaust SmokeClogged or dirty air cleanerService air cleaner.
Engine Emits Black or Gray Exhaust SmokeDefective muffler (back pressure too high)Have dealer check back pressure.
Engine Emits Black or Gray Exhaust SmokeImproper fuelUse correct fuel for temperature.
Engine Emits Black or Gray Exhaust SmokeInjection nozzles dirtySee your dealer.
Engine Emits Black or Gray Exhaust SmokeEngine out of timeSee your dealer.
Engine Emits White SmokeImproper fuelUse correct fuel for temperature.
Engine Emits White SmokeCold engineWarm up engine to normal operating temperature.
Engine Emits White SmokeDefective thermostatRemove and check thermostat.
Engine Emits White SmokeEngine out of timeSee your dealer.

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.

Repair guides

3

Step-by-step procedures compiled from the Northern Lights service manual for this model.

Parts

5
Part #DescriptionQtySystem
130336020Secondary fuel filter1Fuel filter Amazon eBay $24.71
24-03100Lube oil filter1Oil filter Amazon eBay $23.45 NAPA $12.88
24-23100Air cleaner elementAir filter Amazon eBay FridayParts $193.84
314531127Element (marked #314531065)1Air filter Amazon eBay $100.00 NAPA $69.76
O843KBattery connections.1Battery connections Amazon eBay

Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

RatingLoadL/hgal/h
Prime100%4.161.1

Available documents

Operator's manual — O843K (Northern Lights)

This page was generated from the 1 manufacturer document above by automated extraction; every figure shown is copied from one of them. How the data is compiled.

Full service, cheapest listings

Priced items from this model's own parts manual.

Fuel filter 130336020$24.71
Oil filter 24-03100$12.88
2 priced items$37.59