Northern Lights L844-2 Engine

⚠ Valve adjustments should be done after the cylinder head bolts have been re-tightened.

Tools: adjustment screw, lock nut wrench

1. Adjust valve clearance after 1000 hours or as needed; engine must be cold and NOT running.
2. Turn the engine over by hand until the inlet valve starts to open and exhaust starts to close (valves rocking).
3. Turn the crankshaft one more full turn; align the top mark of the crank pulley with the top mark of the timing gear case.
4. Loosen the lock nut and adjust clearance between rocker arm and valve guide with the adjustment screw.
5. Clearance on both intake and exhaust valves should be 0.008 in. (0.2 mm).
6. Repeat for each cylinder; each set of valves must be adjusted individually.
7. Replace the rocker arm cover and tighten cover nuts to 5 - 8 ft/lbs (0.8 - 2.3 kg/m).

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 steam can cause severe burns.

1. Check the temperature gauge; if above 205°F (96°C) shut off the engine immediately.
2. Use the Troubleshooting Guide to isolate the cause of the overheat.
3. Make repairs and restart after the temperature gauge registers below 200°F (94°C).
4. If shutdown activated with normal temperature, check crankcase oil level.
5. If oil level is low, fill with recommended oil and restart, watching oil pressure (20-60 PSI).
6. If oil level is normal, do NOT restart the engine; call your dealer.

Tools: dipstick

1. Check the oil level in the crankcase with the dipstick.
2. The oil level must be in the waffled area on the stick; never allow it to go below this area.
3. Add the same viscosity of oil as is already in the crankcase.

⚠ 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.

Tools: cardboard or wood

1. Loosen bleed bolt A on top of the filter.
2. Pump hand primer B on the fuel lift pump until pure fuel (no bubbles) escapes from bleed bolt A; tighten bleed screw A.
3. Loosen bleed screw C and pump hand primer B until pure fuel escapes; tighten bleed screw C.
4. If the engine does not start, loosen a fuel line at the injector and crank with the starter until pure fuel escapes; tighten. Do each line one at a time.
5. After starting, use a piece of cardboard to look for fuel leaks.

⚠ Close the sea-cock before working on the engine cooling system.

⚠ Allow the engine to cool before working on the cooling system.

Tools: cap pressure tester

1. Check the coolant level each day before starting the engine.
2. Remove the pressure cap from the expansion tank.
3. Level should be about 1 in. (2.5 cm) below the filler cap sealing surface when the engine is cold.
4. Use a cap pressure tester to check the cap if it is suspected faulty.

1. Flush the cooling system every 2500 hours or every 12 months, whichever comes first.
2. Remove expansion tank cap and drain the engine block.
3. Open block drain cock and remove hose from bottom of heat exchanger tank.
4. Pour clean water into the expansion tank until water from the drains is free of discoloration and sediment.
5. Let water drain completely, close drains and refill with recommended mixture.
6. Check hoses and connections and repair any leakage.

Tools: metal rod

1. Clean the heat exchanger core once a year or after 2500 hours of operation.
2. Drain the expansion tank and heat exchanger.
3. Remove heat exchanger end covers and remove the core.
4. Clean the inside of the core tubes using a metal rod; flush, inspect and clean again if necessary.
5. Reassemble, fill the cooling system, start the engine and check for leaks.

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

Tools: needle-nose pliers or two screwdrivers

1. Change the seawater pump impeller every 1000 hours, or as needed.
2. Remove the pump end cover; pry out the impeller using needle-nose pliers or two screwdrivers.
3. Be sure all pieces of a failed impeller are removed.
4. Clean the inside of the housing.
5. Press in the new impeller and place sealing washers in the outer end of the impeller center.
6. Replace the cover using a new gasket.

Tools: hydrometer

1. Check electrolyte level daily and add distilled water to manufacturer's recommended level.
2. Check and clean batteries, cables and terminals every 100 hours.
3. Clean corrosion with a 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.

⚠ Never use a flushing oil or put additives in the crankcase.

1. Change the engine oil and oil filter after 50 hours; use Service CC 30 weight oil during the first 100 hours.
2. Change oil and filter again at 100 hours, then every 250 hours.
3. In intermittent cold weather, change oil every 100 hours or six weeks, whichever comes first.
4. Change oil at the end of each season and the beginning of each season.
5. Change oil when engine is warm.
6. Loosen the clamp on the oil change tube, remove cap, drain oil, replace cap and tube.
7. Refill engine with recommended oil for the season.
8. Dispose of waste oil in an approved manner.

1. Drain fresh water and seawater cooling systems completely; shut off seacocks before opening drain cocks.
2. Drain water supply lines and wet exhaust line.
3. Loosen the seawater pump cover and drain the pump.
4. Change the crankcase oil and filter.
5. Loosen the alternator belt.
6. Disconnect and clean battery; remove to warm storage if possible.
7. Clean outside of unit; paint scratched or chipped surfaces and apply corrosion preventative to exposed metal.