Northern Lights M20C Generator Set

Tools: Torque wrench

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

Tools: Adjustment screw, Lock nut, Wrench

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

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

Tools: D.C. test bulb

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

Tools: DC test bulb

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

Tools: D.C. test bulb

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

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

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

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

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

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

⚠ 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

1. Loosen bleed bolt “A” on top of the filter.
2. Pump hand primer “B” on fuel lift pump until pure fuel (no bubbles) escapes from bleed bolt “A”. Tighten bleed screw “A”.
3. Loosen bleed screw “C”. Pump hand primer “B” until pure fuel escapes. Then tighten bleed screw “C”.
4. 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.
5. After the engine has started, use a piece of cardboard to look for fuel leaks.

⚠ 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.

1. The fuel system is self-bleeding but may need manual bleeding after filter change, run-out of fuel, or component removal.
2. Loosen bleed bolt 'A' on top of filter.
3. Pump hand primer 'B' on fuel lift pump until pure fuel (no bubbles) escapes from bleed bolt 'A'. Tighten bleed screw 'A'.
4. Loosen bleed screw or bolt 'C'. Pump hand primer 'B' until pure fuel escapes. Tighten bleed screw 'C'.
5. If engine does not start, loosen a fuel line at the injector, crank until pure fuel escapes, and tighten. Do each line one at a time.
6. After engine has started, use a piece of cardboard to look for fuel leaks.

⚠ Battery gas can explode. Keep all flames and sparks away from batteries.

1. Before changing or using booster batteries, check battery electrolyte level; add distilled water if necessary.
2. Booster and main batteries must have the same voltage rating.
3. Connect positive (+) terminal of booster battery to positive (+) terminal of main battery.
4. Connect negative (-) terminal of booster battery to ground on the engine block.
5. Remove booster battery after starting engine.

1. The first 100 hours on a new or reconditioned engine are critical to its life and performance.
2. Maintain at least a 75% load for the first 100 hours; if not possible, no less than 50% load.
3. Vary the load to help seat the piston rings.
4. Frequently check engine temperature and oil pressure gauges (Series 3 or 4 panels).
5. Change engine oil and filter at 50 hours.
6. Change oil and filter again at 100 hours.