Northern Lights NL374 Generator Set

⚠ Adjust valves after cylinder head bolts have been tightened

Tools: feeler gauge

1. Adjust after first 50 hours, then every 600 hours.
2. Do adjustment with engine cold and not running; remove rocker arm cover.
3. Turn engine by hand until valves rock, then one more full turn.
4. Loosen lock nut and adjust clearance with adjustment screw.
5. Set both intake and exhaust to 0.006-0.010 in (0.15-0.25 mm).
6. Repeat for each cylinder and replace rocker arm cover.

1. Press belt with thumb at midpoint between crankshaft and alternator pulleys.
2. Tension is correct when belt depresses about 3/8 inch (10-15 mm).

⚠ Escaping diesel fuel under pressure can penetrate skin and cause serious injury

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

1. Loosen bleed screw on top of fuel filter.
2. Pump hand primer on fuel lift pump until pure fuel with no bubbles escapes.
3. Tighten bleed screw.
4. Loosen bleed screw on injection pump, pump primer until bubble-free, tighten.
5. If engine will not start, loosen a fuel line at the injector and crank until pure fuel escapes.

⚠ Overtightening can damage filter housing

⚠ Never use a flushing oil

Tools: filter wrench

1. Loosen plug in oil pan and drain oil; dispose of waste oil properly.
2. Remove old filter with a filter wrench; discard old gasket.
3. Clean mount face and oil the new filter gasket.
4. Screw filter on until gasket meets sealing surface, then 1/2 turn by hand.
5. Fill engine with recommended oil.
6. Start engine, check for leakage, stop, wait 3 minutes, check level.

⚠ Allow engine to cool before working on cooling system

⚠ Open filler cap carefully using protective clothing

1. Flush every 600 hours or every 12 months, whichever comes first.
2. Remove radiator cap and open radiator and engine block drains.
3. Flush until water from both drains is clear of discoloration.
4. Drain completely and refill with recommended coolant mixture.
5. Check hoses and connections and repair any leakage.
6. Start engine, run 5 minutes, shut down, let cool, check coolant level.

⚠ Do not run engine with air cleaner removed

⚠ Ensure no impurities enter engine while changing element

1. Check dust trap daily; squeeze rubber cap lips to empty dirt.
2. Visually inspect air cleaner every 100 hours.
3. Replace element when necessary; an element cannot be cleaned.

⚠ Store the set in a dry, protected place

1. Drain and flush radiator and cooling system; leave dry or refill with antifreeze mixture.
2. Fill fuel tank or add biocide per manufacturer instructions.
3. Seal air cleaner inlet, exhaust opening, crankcase breather pipe and fuel tank vent.
4. Change 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 and put corrosion preventative on exposed metal.

⚠ Open the filler cap only when the engine is cold

1. Check water level; about 1 in (2.5 cm) below filler cap sealing surface when cold.
2. Check crankcase oil level between high and low marks on dipstick.
3. Check fuel tank level and open fuel valves at tank and secondary filter.
4. Turn on optional battery switch if installed.

⚠ Holding preheat switch on too long can burn out heater elements

⚠ Excessive cranking may cause engine damage

1. Hold Shutdown Bypass-Preheat Switch ON 10 to 20 seconds before starting a cold engine.
2. While holding the switch ON, push Engine Control Switch to START.
3. Release both switches as soon as engine starts.
4. Do not crank starter more than 20 seconds.

1. Remove electrical load from generator set.
2. Run engine 3 to 5 minute cool down period.
3. Move engine control switch to STOP until engine stops completely.
4. Shut off fuel valve at tank.

⚠ Do not use pry bars to remove injectors from cylinder head

⚠ Overtightening can damage injector

⚠ DO NOT use hand to check for leaks

Tools: 20mm wrench or socket

1. Clean loose dirt from around injectors and fuel lines.
2. Relieve high pressure by loosening delivery line flare nuts at each injector.
3. Remove delivery lines as an assembly; keep ends covered.
4. Remove return line clamps and return lines.
5. Unscrew injector with a 20 mm wrench or socket.
6. Install new copper sealing washer and screw injector in to 36-39 ft-lbs (5.0-5.4 kgf-m).
7. Install return and delivery lines; leave loose at injectors for bleeding.

Tools: torque wrench

1. Retighten head bolts after first 50 hours with engine cold.
2. Remove rocker arm cover.
3. Tighten bolts in the torque sequence in 2 or 3 passes.
4. End at specified torque on final pass and replace rocker arm cover.