Northern Lights ML844 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.

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.

⚠ 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.

⚠ 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.

⚠ Use extreme caution when working on hot engines to avoid burns. Allow engine to cool before working on the cooling system.

1. Flush the cooling system every 600 hours or every 12 months, whichever comes first.
2. Marine: Remove expansion tank cap and drain engine block. Open block drain cock. Remove hose from bottom of heat exchanger tank.
3. Marine: Pour clean water into expansion tank until water from drains is free of discoloration and sediment. Drain completely, close drains and refill with recommended mixture.
4. Industrial: Remove radiator cap and open drain cocks on radiator and engine block.
5. Industrial: Pour clean water into radiator until clear of discoloration; close radiator drain and continue flushing until engine drain water is clear.
6. Industrial: Open all drain cocks and drain completely; close drain cock and refill with recommended coolant mixture.
7. Industrial: Clean leaves, dust and other debris off radiator fins.
8. Check hoses and connections and repair any leakage.

⚠ 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 the water level by removing the pressure cap from the expansion tank or radiator.
2. Check the oil level in the crankcase with the dipstick; level must be in the waffled area.
3. Check the fuel tank level and open any fuel valves.
4. Marine sets: close the seacock, check and clean the sea strainer and reopen the seacock.
5. Marine sets: place the battery switch in the ON position.

⚠ Do not crank starter for more than 20 seconds.

⚠ Holding switch on too long can burn out the glow plugs.

⚠ Excessive cranking of starter on marine sets equipped with water lift muffler can cause engine damage.

1. Hold Shutdown Bypass-Preheat Switch in ON position for 10 to 20 seconds before starting a cold engine.
2. While holding the Bypass-Preheat Switch, push Engine Control Switch to START position.
3. As soon as the engine starts, release both switches.
4. Let the unit run unloaded for a three to five minute warm-up period.
5. Add electrical load.

1. Remove electrical load from generator set.
2. Run engine for a 3 to 5 minute cool down period.
3. Move engine control switch to the STOP position momentarily.
4. Marine sets: shut off seacock, fuel valve and battery switch.

⚠ Do NOT use hand to check for leaks.

⚠ Overtightening can damage injector.

1. Install a new copper sealing washer in each injector hole.
2. Screw in injector and tighten to 44-51 ft/lbs (6 to 7 Kgm).
3. Install return line using new sealing washer below each connection. Tighten return line retaining bolts to 22-30 ft/lbs.
4. Install delivery lines. Leave loose at injectors for bleeding.
5. Crank engine to fill lines. Tighten lines at injectors to 11-18 ft./lbs.
6. Start engine and check for leaks using a piece of paper or cardboard.