Northern Lights L6125H Engine

⚠ Drainage window must be positioned at bottom of primary element or system will malfunction.

⚠ Both first stage and coalescing elements must be replaced at the same time.

1. Remove v-band clamp or retaining springs and air filter.
2. Carefully remove silencer lid and o-rings.
3. Raise service handle on oil separator element and pull it out with equal force.
4. Reach inside housing and pull first element stage down; discard both elements.
5. Reassemble with new elements, o-rings, silencer lid, v-band or retaining springs, and air filter.

⚠ Escaping diesel fuel under pressure can penetrate skin; relieve pressure before disconnecting lines.

⚠ Due to High Pressure Common Rail design, open valve C on bottom of water separator bowl to relieve pressure before removing filters.

Tools: Special tool #53-50005

1. Normally use hand primer; if engine ran out of fuel or system has air, use special tool #53-50005.
2. Open drain valve on fuel filter and use hand primer to drain water and contaminants.
3. Attach open line to diagnostic port above hand primer; put line end in diesel fuel container.
4. Pump hand primer until steady flow of fuel without bubbles comes out.
5. Disconnect line from diagnostic port.
6. Close return line.
7. Pump primer until firm.
8. Crank engine until it starts; 15 seconds maximum, 60 seconds rest.
9. Open return line.

⚠ Overtightening can damage filter housing.

Tools: Filter wrench

1. Use a filter wrench to remove old filter; dispose of filter in approved manner.
2. Make sure old filter gasket is removed and discarded.
3. Lubricate rubber gasket on new filter.
4. Screw filter onto nipple until gasket meets sealing surface.
5. Using hands only, tighten filter one-half turn farther.
6. Fill engine with recommended oil.
7. Start engine and check for leakage; stop engine and check oil level.

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

1. Stop engine and allow it to be cold.
2. Close seacock.
3. Remove pressure cap from expansion tank; if applicable, open cooling system air vent on turbocharger.
4. Open drains on exhaust manifold and engine block; drain fresh water system.
5. For keel cooling, vessel must be out of water to drain keel cooler.
6. Pour clean water into expansion tank until drain water is clear and free of sediment; close drains.
7. Fill fresh water system with recommended coolant mixture.
8. Close cooling system air vent on turbocharger.
9. Open seacock.
10. Start engine; check hoses and connections and repair leakage.

1. Drain cooling system.
2. Remove cooling water pipes between heat exchanger and water pump inlet.
3. Disconnect hose to seawater pump.
4. Unscrew attaching bolts holding heat exchanger to expansion tank.
5. Remove bolts holding heat exchanger cover.
6. Wash core inside and out; chemical agents may be used if necessary.
7. Clean accessible parts of heat exchanger housing.
8. Reassemble using new gaskets and sealing rings.

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

Tools: Water pump pliers

1. Remove pump end cover.
2. Remove impeller with water pump pliers; remove all pieces of a failed impeller.
3. Clean inside of housing.
4. Press in new impeller.
5. Place sealing washer in outer end of impeller center if not already done.
6. Replace cover using a new gasket.

1. Change oil and replace filter.
2. Service air cleaner.
3. For storage of a year or more, drain, flush, and refill cooling system with appropriate coolant.
4. Remove fan and alternator belts, optional.
5. Remove and clean batteries; store them fully charged in a cool dry place.
6. Disengage clutch to engine drivelines.
7. Clean exterior of engine with salt-free water and touch up painted surfaces.
8. Coat exposed machined metal surfaces with grease or corrosion inhibitors if they cannot be painted.
9. Seal all openings with plastic bags and tape.
10. Store engine in a dry protected place; cover if outside.

Tools: Scraper or steel brush

1. Drain raw water from heat exchanger.
2. Remove zinc holders from back of tank and front and port side of heat exchanger.
3. Scrape or steel brush zinc electrode clean.
4. Replace electrode if more than 50% has eroded away.
5. Reinstall zinc holders; ensure threads are clean and have good metal-to-metal contact.

⚠ Use protective clothing and open filler cap carefully when engine is warm to prevent burns.

1. Check expansion tank water level; it should be about 1 3/4 in. (4-5 cm) below filler cap sealing surface when cold.
2. Open turbocharger venting cock when filling coolant to avoid air pockets.
3. Check crankcase oil level with dipstick; keep between waffled area and Add.
4. Check fuel tank level and open fuel valves; inspect lines for leakage.
5. Check reverse gear oil level and for leakage.
6. Close seacock, clean strainer, and reopen seacock.
7. Place battery switch in ON position.

⚠ Shut down engine if water temperature rises above 200°F (94°C).

1. Check oil pressure as soon as engine starts; it should be above 15 PSI.
2. Check voltmeter; it should read 26-28 volts at 60°F (16°C).
3. Water temperature should not rise over 200°F (94°C); shut down and investigate if it does.
4. Do not exceed 800 RPM when shifting marine gear.
5. Low idle is 650 RPM.
6. Maximum working speed is 2100 RPM High Output, 1900 RPM Medium Duty, or 1800 RPM Continuous Duty.
7. Establish maximum cruising RPM by subtracting 200-300 RPM from full-throttle RPM.

⚠ Do not turn battery switch to OFF while engine is running.

1. Run engine three to five minutes in neutral at 1000 RPM for cool down.
2. Return engine to low idle.
3. Turn key switch counterclockwise as far as possible to stop engine.
4. Close seacock and fuel valves.
5. Put battery switch in OFF position.

⚠ Do not crank starter for more than 15 seconds consecutively.

⚠ Never race a cold engine.

1. Put gear control in neutral.
2. Move throttle control to idle position.
3. Turn key switch to first position; voltmeter should not read below 24 volts.
4. Turn key to starting position; release key as soon as engine starts.
5. Move throttle up until engine runs at approximately 1000 RPM.
6. Do not crank starter more than 15 seconds consecutively.
7. Operate at 1000 RPM for a 3 to 5 minute warm-up period.