Northern Lights L643 Engine

Tools: feeler gauge, wrenches

1. Retighten cylinder head bolts first; engine must be cold and NOT running.
2. Turn engine by hand until #1 cylinder inlet valve starts to open and exhaust valve starts to close.
3. Turn the crankshaft one more full turn and adjust both valves for this cylinder.
4. Loosen the lock nut and adjust clearance between rocker arm and valve guide with the adjustment screw.
5. Set clearance to 0.008 in. (0.2 mm) on both intake and exhaust valves.
6. Repeat for each cylinder; each set of valves must be adjusted individually.
7. Replace rocker arm cover and tighten cover nuts to 7.2 - 8.7 ft/lbs (1.0 - 1.2 kg/m).

⚠ The AVR must be disconnected when flashing fields or it could be ruined.

Tools: 12 volt DC source, voltmeter

1. If there is no voltage buildup on startup (zero volts measured), the generator may have no residual magnetic field.
2. Disconnect the AVR before flashing fields or it could be ruined.
3. Apply 12 volts DC to terminals K (-) and J (+) as indicated.
4. Reconnect AVR and check voltage buildup.

⚠ Escaping diesel fuel under pressure can penetrate skin causing serious personal injury.

⚠ Use cardboard or wood, not hands, to search for leaks.

Tools: cardboard or wood for leak checking

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

⚠ Overtightening can damage the filter housing.

Tools: filter wrench

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

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

⚠ Keep an extra impeller and cover gasket in reserve on board.

Tools: needle-nose pliers, 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.
4. Be sure all pieces of a failed impeller are removed.
5. Clean the inside of the housing.
6. Press in the new impeller and place the sealing washers in the outer end of the impeller center.
7. Replace the cover using a new gasket.

Tools: dipstick

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

⚠ Be sure to close the sea-cock before working on the engine cooling system.

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

1. Marine: remove expansion tank cap and drain engine block; open block drain cock.
2. Marine: pour clean water into expansion tank until water from drains is free of discoloration and sediment.
3. Marine: let water 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 water runs clear; close radiator drain.
6. Industrial: continue flushing until water from engine drain is clear; open all drains and drain completely.
7. Industrial: close drain cock, refill with recommended coolant mixture and clean radiator fins.
8. Check hoses and connections and repair any leakage.

⚠ Dispose of waste oil in an approved manner.

⚠ Never use a flushing oil.

1. Change oil when the engine is warm.
2. Loosen the clamp on the oil change tube and remove the cap; drain the oil.
3. Replace the cap and tube.
4. Refill the engine with recommended oil.

Tools: torque wrench

1. Retighten the head bolts after the first 50 hours.
2. Tighten bolts when the engine is cold.
3. Loosen the nuts and remove the rocker arm cover.
4. Tighten head bolts with a torque wrench in the order shown, evenly in 2 or 3 passes.
5. End at the specified torque in the final pass: 26 - 29 ft/lbs (3.5 - 4.0 kg/m).

⚠ Store the set in a dry, protected place; if stored outside, protect with a cover.

1. Marine: drain fresh water and seawater cooling systems completely; shut off seacocks before opening drain cocks.
2. Marine: drain water supply lines and wet exhaust line; loosen seawater pump cover and drain pump.
3. Industrial: drain and flush radiator and cooling system; leave dry or refill with antifreeze-water mixture.
4. Industrial: fill the fuel tank or add biocide per manufacturer's instructions.
5. Industrial: seal air cleaner inlet, exhaust opening, crankcase breather pipe and fuel tank vent with plastic bags and tape.
6. Change the crankcase oil and filter.
7. Loosen the alternator belt.
8. Disconnect and clean battery; remove to warm storage if possible.
9. Clean outside of unit and put corrosion preventative on all exposed metal surfaces.

⚠ Excessive cranking of marine sets with a water lift muffler can cause engine damage.

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

1. Hold Shutdown Bypass-Preheat switch ON 10 to 20 seconds before starting a cold engine.
2. While holding the preheat switch ON, push the Engine Control switch to START.
3. As soon as the engine starts, release both switches.
4. Do not crank the starter for more than 20 seconds consecutively.
5. If the engine fails to start on the first attempt, be sure it has stopped completely before re-engaging.
6. If no start after three 20-second cranks, remove the impeller from the raw water pump.
7. Once the engine starts, shut it off immediately and re-install the impeller.
8. Restart the engine and check the exhaust overboard outlet for gushes of water.

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