Northern Lights NL844 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: feeler gauge, wrench

1. Adjust valve clearance after first 50 hours, then at 1000 hours or as needed.
2. Engine should be cold and NOT running.
3. Turn engine by hand until inlet valve starts to open and exhaust valve starts to close.
4. Turn crankshaft one more full turn; align top mark of crank pulley with TOP mark of timing gear case.
5. Loosen lock nut and adjust clearance between rocker arm and valve guide with adjustment screw.
6. Repeat for each cylinder; each set of valves adjusted individually.
7. Replace rocker arm cover and tighten cover nuts.

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: 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.

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

⚠ Always remove grounded (-) battery clamp first and replace ground clamp last.

⚠ Booster and main batteries must have the same voltage rating.

Tools: hydrometer

1. Check electrolyte level daily; 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 250 hours.
6. For boosting: connect positive booster terminal to positive main battery terminal.
7. Connect negative booster terminal to ground on the engine block.
8. Remove booster battery after starting engine.

⚠ 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, cardboard

1. Loosen bleed bolt A on top of the filter.
2. Pump hand primer B on fuel lift pump until pure fuel with no bubbles escapes.
3. Tighten bleed screw A.
4. Loosen bleed screw C; pump hand primer until pure fuel escapes, then tighten.
5. If engine does not start, loosen a fuel line at injector and crank until pure fuel escapes; tighten.
6. Do each line one at a time.
7. After starting, 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.

⚠ Overtightening can damage the filter housing.

⚠ No wrench when tightening.

Tools: filter wrench

1. Change the lube oil filter every 250 hours.
2. Use a filter wrench to remove old filter and dispose of it properly.
3. Make sure old gasket is removed and discarded; clean mount face.
4. Spread thin film of engine oil on new filter gasket and screw on until gasket meets sealing surface.
5. Using hands only, tighten filter one-half turn farther.
6. Fill engine with recommended oil, start, check for leakage; stop, wait 3 minutes, check level.

⚠ Never use a flushing oil.

⚠ Never put additives or flushing oil in crankcase.

1. Change the engine oil and oil filter after 50 hours of operation.
2. Use RPM Delo Series 100, 30 weight or equivalent Service CC 30 weight oil during the first 100 hours.
3. Change the oil and filter again at 100 hours using recommended oil, then every 100 hours.
4. Change oil every 100 hours or six weeks in intermittent cold weather.
5. Loosen clamp on oil change tube. Remove cap. Drain oil. Replace cap and tube.
6. Refill engine with recommended oil.
7. Change oil when engine is warm and dispose of waste oil in an approved manner.

⚠ Overtightening can do damage to filter housing.

Tools: Filter wrench

1. Change the lube oil filter every 100 hours.
2. Use a filter wrench to remove old filter. Dispose of filter in approved manner.
3. Make sure the gasket from the old filter is removed and discarded. Clean mount face.
4. Spread a thin film of engine oil on the rubber gasket of the new filter.
5. Screw filter onto nipple until gasket meets the sealing surface.
6. Using hands only, no wrench, tighten filter one-half turn farther.
7. Fill engine with recommended oil. Start engine and check for leakage.
8. Stop engine, wait 3 minutes, and check oil level. Add oil if necessary.

⚠ Place some kind of protection under the screwdrivers in order not to damage the pump housing.

⚠ Make sure that there is always an extra impeller and cover gasket in reserve on board.

Tools: Needle-nose pliers or two screwdrivers

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

⚠ Cooling water reaches extremely high temperatures; allow engine to cool before working.

⚠ Open filler cap carefully using protective clothing.

1. Flush cooling system every 2500 hours or every 12 months, whichever comes first.
2. Remove radiator cap, radiator drain and drain engine block.
3. Pour clean water into radiator until water is free of discoloration and sediment.
4. Close radiator drain and continue flushing until engine drain water is clear.
5. Open all drain cocks and drain completely.
6. Close drain cock and refill with recommended mixture.
7. Clean leaves, dust and other debris off radiator fins.