Northern Lights M984 troubleshooting: 79 symptom-cause-remedy entries from the manufacturer's own service documentation.
Northern Lights M984 — full specs, parts & maintenance.
| Symptom | Cause | Remedy |
|---|---|---|
| Battery Will Not Charge | Loose or corroded connections | Clean and tighten battery connections. |
| Battery Will Not Charge | Sulfated or worn out batteries | Check specific gravity of each battery; Check electrolyte level of each battery. |
| Battery Will Not Charge | Loose or defective alternator belt | Adjust belt tension; Replace belt. |
| Starter Inoperative | Check DC circuit breaker | If the breaker is tripped, reset it. |
| Starter Inoperative | Loose or corroded connections | Clean and tighten loose battery and harness plug connection. |
| Starter Inoperative | Low battery condition | Check specific gravity of each battery; Check electrolyte level of each battery. |
| Starter Inoperative | Defective electrical system ground wire | Repair or replace. |
| Starter Cranks Slowly | Low battery condition | Check specific gravity of each battery; Check electrolyte level of each battery; Replace battery if necessary; If low, fill cells with distilled water. |
| Starter Cranks Slowly | Crankcase oil too heavy | Fill with oil of appropriate viscosity. |
| Starter Cranks Slowly | Loose or corroded connections | Clean and tighten loose connections. |
| Starter Cranks Slowly | Battery is too small; Battery cables are too small | |
| Entire Electrical System Does Not Function | Check DC circuit breaker | If breaker is tripped, reset it. |
| Entire Electrical System Does Not Function | Faulty connection | Clean and tighten battery and harness plug connections. |
| Entire Electrical System Does Not Function | Sulfated or worn out batteries | Check specific gravity and electrolyte level of each battery. |
| Engine Hard to Start or Will Not Start | Improper starting procedure | See starting section of this manual. Take special note of Bypass Switch operation. |
| Engine Hard to Start or Will Not Start | No fuel | Check level of fuel in fuel tank. |
| Engine Hard to Start or Will Not Start | Low battery condition | Check electrolyte level and condition. |
| Engine Hard to Start or Will Not Start | Excessive resistance in starting circuit | Clean and tighten all battery connections. |
| Engine Hard to Start or Will Not Start | Crankcase oil too heavy | Use oil of proper viscosity. |
| Engine Hard to Start or Will Not Start | Improper type of fuel | Consult fuel supplier and use proper type of fuel for operating condition. |
| Engine Hard to Start or Will Not Start | Water, dirt or air in fuel system | Drain, flush, fill and bleed system. |
| Engine Hard to Start or Will Not Start | Clogged primary fuel filter element | Clean or replace filter element. |
| Engine Hard to Start or Will Not Start | Clogged secondary fuel filter element | Replace filter element. |
| Engine Hard to Start or Will Not Start | Dirty or faulty injection nozzles | Have your dealer check injection nozzles. |
| Engine Runs Irregularly or Stalls Frequently | Below normal engine temperature | Remove and check thermostat. |
| Engine Runs Irregularly or Stalls Frequently | Clogged primary fuel filter element | Clean or replace filter element. |
| Engine Runs Irregularly or Stalls Frequently | Clogged secondary fuel filter element | Replace secondary filter element. |
| Engine Runs Irregularly or Stalls Frequently | Water or dirt in the fuel system | Drain, flush, fill and bleed system. |
| Engine Runs Irregularly or Stalls Frequently | Dirty or faulty injection nozzles | Have your dealer check injection nozzles. |
| Engine Runs Irregularly or Stalls Frequently | Air in fuel system | Inspect clamps and hoses on suction side of fuel pump for air leak. |
| Engine Runs Irregularly or Stalls Frequently | Improper type of fuel | Consult fuel supplier and use proper type of fuel for operating condition. |
| Lack of Engine Power | Engine overloaded | Reduce the load. |
| Lack of Engine Power | Intake air restriction | Service air cleaner. |
| Lack of Engine Power | Clogged primary fuel filter element | Clean or replace filter element. |
| Lack of Engine Power | Clogged secondary fuel filter element | Replace filter element. |
| Lack of Engine Power | Improper type of fuel | Consult fuel supplier and use proper type of fuel for operating conditions. |
| Lack of Engine Power | Overheated engine | See "Engine Overheats" in next category. |
| Lack of Engine Power | Below normal engine temperature | Remove and check thermostat. |
| Lack of Engine Power | Improper valve clearance | Reset valves. Best done by dealer. |
| Lack of Engine Power | Dirty or faulty injection nozzles | Replace injectors. Best done by dealer; See your local dealer. |
| Engine Overheats | Engine overloaded | Reduce the electrical load. |
| Engine Overheats | Low coolant level | Fill tank or radiator to proper level; Check hoses for loose connections and leaks. |
| Engine Overheats | Keel cooling tubes (marine sets) have been painted | Remove paint from tubes. |
| Engine Overheats | Cooling system needs flushing | Flush cooling system. |
| Engine Overheats | Defective thermostat | Remove and check thermostat. |
| Engine Overheats | Defective temperature gauge | Check water temperature with thermometer and replace gauge if necessary. |
| Engine Overheats | Water pump impeller worn or broken | Check the impeller and replace if necessary. |
| Engine Knocks | Insufficient oil | Call your dealer. |
| Engine Knocks | Injection pump out of time | Call your dealer. |
| Engine Knocks | Below normal engine temperature | Check your thermostats; Check water temperature to see if temperature gauge is working properly. |
| Engine Knocks | Faulty fuel injector | Call your dealer. |
| Engine Knocks | Engine overheating | See "Engine Overheating" section. |
| High Fuel Consumption | Improper type of fuel | Use correct fuel for temperature. |
| High Fuel Consumption | Clogged or dirty air cleaner | Service air cleaner. |
| High Fuel Consumption | Engine overloaded | Reduce the electrical load. |
| High Fuel Consumption | Improper valve clearance | See your dealer. |
| High Fuel Consumption | Injection nozzles dirty | See your dealer. |
| High Fuel Consumption | Injection pump out of time | See your dealer. |
| High Fuel Consumption | Engine not at proper temperature | Check your thermostats; Check water temperature with thermometer and replace gauge if necessary. |
| Below Normal Engine Temperature | Thermostats not working properly | Check thermostats. |
| Below Normal Engine Temperature | Temperature gauge not working properly | Check water temperature with thermometer. |
| Low Oil Pressure | Low oil level | Fill crankcase to proper level. |
| Low Oil Pressure | Improper type of oil | Drain and fill crankcase with correct oil. |
| Low Oil Pressure | Partially plugged oil filter | Replace filter. |
| High Oil Consumption | Break-in period | Oil consumption decreases after break in. |
| High Oil Consumption | Crankcase oil too light | Use proper viscosity oil. |
| High Oil Consumption | Oil leaks | Check for leaks in lines around gaskets and drain plug. |
| High Oil Consumption | Crankcase over full | Remove excess oil. |
| Engine Emits Black or Gray Exhaust Smoke | Clogged or dirty air cleaner | Service air cleaner. |
| Engine Emits Black or Gray Exhaust Smoke | Defective muffler (back pressure too high) | Have dealer check back pressure. |
| Engine Emits Black or Gray Exhaust Smoke | Improper fuel | Use correct fuel for temperature. |
| Engine Emits Black or Gray Exhaust Smoke | Engine overloaded | Reduce the electrical load. |
| Engine Emits Black or Gray Exhaust Smoke | Injection nozzles dirty | See your dealer. |
| Engine Emits Black or Gray Exhaust Smoke | Engine out of time | See your dealer. |
| Engine Emits White Smoke | Improper fuel | Use correct fuel for temperature. |
| Engine Emits White Smoke | Cold engine | Warm up engine to normal operating temperature. |
| Engine Emits White Smoke | Defective thermostat | Remove and check thermostat. |
| Engine Emits White Smoke | Engine out of time | See your dealer. |
| Low Compression Pressure | See your dealer. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Improper starting procedure; No fuel; Low battery condition; Excessive resistance in starting circuit. See the table for the matching fixes.
Documented causes: Engine overloaded; Intake air restriction; Clogged primary fuel filter element; Clogged secondary fuel filter element. See the table for the matching fixes.
Documented causes: Below normal engine temperature; Clogged primary fuel filter element; Clogged secondary fuel filter element; Water or dirt in the fuel system. See the table for the matching fixes.