Maintenance schedule
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Oil | 4.2 qt | — | 200 hr |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
The Northern Lights L731 is a 1.13 L 3-cylinder natural engine rated at 1800 rpm. It powers generator sets from Northern Lights, including the M773L. It holds 4 L (1.1 gal) of oil.
Also known as: Lugger L731
| Oil capacity | 4.0 L |
|---|---|
| Displacement | 1.13 L |
| Cylinders | 3 |
| Aspiration | natural |
| Rated speed | 1800 rpm |
How to read your Northern Lights engine serial & model number →
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Oil | 4.2 qt | — | 200 hr |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Aceite del motor y filtro | Change | 50 hr | First service — Período de adaptación; también a las 100 horas (PS2/PS3) | |
| Ajustes de las válvulas | Adjust | 50 hr | First service — PS6; después de las primeras 50 horas | |
| Nivel de electrolito de las baterías | Check | 50 hr | 1 mo | PS18 |
| Tensión de la correa trapezoidal | Inspect | 50 hr | PS5 | |
| Aletas del radiador | Clean | 100 hr | PS16; sólo equipos industriales | |
| V-belt tension | Check | 100 hr | SP6 per schedule summary; SP-5 text calls for daily check | |
| battery electrolyte level | Check | 100 hr | SP17 | |
| Aceite del motor | Change | 200 hr | PS2; cada 100 horas o 6 semanas en tiempo frío, lo que llegue primero | |
| Filtro del aire | Inspect | 200 hr | PS4; más a menudo bajo condiciones de mucho polvo | |
| Filtro primario del combustible (marca Racor) | Change | 200 hr | PS8; o cuando sea necesario | |
| Filtro secundario del combustible | Change | 200 hr | PS9 | |
| Filtros del aceite lubricante | Change | 200 hr | PS3 | |
| air cleaner | Check | 200 hr | SP4; check more often in dusty conditions | |
| battery condition | Check | 200 hr | SP18 per schedule summary; battery care text gives hydrometer check every 500 hours | |
| engine oil and filter | Change | 200 hr | First service — Every 200 hours (SP2/3); cold intermittent operation: every 100 hours or six weeks | |
| exhaust elbow | Inspect | 500 hr | SP16; sooner if needed; replace if rust or damage | |
| primary fuel filter element | Change | 500 hr | SP8; or as often as necessary | |
| raw water pump impeller | Change | 500 hr | SP15; or as needed | |
| secondary fuel filter | Change | 500 hr | SP9; or as necessary | |
| Ajustes de las válvulas | Inspect | 600 hr | PS6; cada 600 horas / anualmente | |
| Condición de las baterías (hidrómetro) | Test | 600 hr | PS19 | |
| Inyectores | Inspect | 600 hr | PS11 | |
| Rodete de la bomba del agua bruta | Change | 600 hr | PS17; sólo equipos marinos, o cuando sea necesario | |
| Sistema refrigerante | Clean | 600 hr | 12 mo | PS14; limpie con agua cada 600 horas o cada 12 meses, lo que llegue primero |
| air cleaner element | Change | 1000 hr | 24 mo | Every 1000 hours or two years, whichever comes first |
| injectors | Check | 1000 hr | SP12; clean injection nozzles every 1500 hours | |
| valve clearance | Adjust | 1000 hr | SP6; after 1000 hours or as needed | |
| Bomba de inyección del combustible | Inspect | 2400 hr | PS12 | |
| Cambiador de calor | Clean | 2400 hr | 12 mo | PS15; sólo equipos marinos |
| cooling system | Other | 2500 hr | 24 mo | SP11 check and flush; every 2500 hours or every 24 months, whichever comes first |
| fuel injection pump | Check | 2500 hr | SP13; settings, max speed, idle speed and exhaust smoke | |
| heat exchanger | Clean | 2500 hr | 24 mo | SP14; every 24 months, or after 2500 hours, or as needed |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Clearance | Coolant level below filler cap sealing surface | about 1 in. (2.5 cm) | in. (cm) | engine cold |
| Clearance | Deflexión de la correa trapezoidal | 3/16 | pulgada (5 mm) | punto céntrico entre el cigüeñal y las poleas del alternador |
| Clearance | V-belt deflection at midpoint between crankshaft and alternator pulleys | 3/16 in. (5 mm) | in. (mm) | |
| Gap | Valve clearance, intake and exhaust | 0.008 in. (0.2 mm) | in. (mm) | |
| Pressure | Engine oil pressure (Operating) | above 15 PSI | PSI | gauges checked often while operating |
| Pressure | Engine oil pressure normal reading | 20-60 PSI | PSI | after a few seconds of operation |
| Pressure | Expansion tank filler cap release pressure | 7 PSI (0.5 bar) | PSI (bar) | |
| Pressure | Presión del aceite (operación) | arriba de 15 | PSI | |
| Pressure | Presión del aceite normal | 20-60 | PSI | |
| Pressure | Válvula de presión del tapón del refrigerante | aproximadamente 7 | PSI (0.5 bar) | |
| Resistance | Glow plug resistance between terminal and engine block | under 1 ohm | ohm | |
| Speed | Velocidad del motor | 1200 ó 1800 (60 Hz) ó 1500 (50 Hz) | RPM | |
| Temperature | Coolant temperature gauge normal range | 167°F and 194°F (75°C to 90°C) | °F (°C) | operating |
| Temperature | High water temperature shutdown threshold | 205°F (96°C) | °F (°C) | marine units |
| Temperature | Restart temperature after overheat | below 200°F (94°C) | °F (°C) | |
| Temperature | Temperatura de parada de emergencia | arriba de 205 | °F (96°C) | |
| Temperature | Temperatura del agua (operación) | bajo 200 | °F (94°C) | |
| Torque | Injector | 43 or 50 ft/lbs (6 to 7 kgm) | ft/lbs (kgm) | |
| Torque | Injector return line retaining bolts | 22 - 30 ft/lbs | ft/lbs | |
| Torque | Inyector | 43 a 50 | libras por pie (6 a 7 kgm) | |
| Torque | Rocker arm cover nuts | 5 - 8 ft/lbs (0.8 - 2.3 kg/m) | ft/lbs (kg/m) | |
| Torque | Tornillos de retención del tubo de retorno de combustible | 22 - 30 | libras por pie (3.0 - 4.1 kgm) | |
| Torque | Tuercas de la tapa del balancín | 5 - 8 | libras por pie (0.8 - 2.3 kg) | |
| Valve clearance | Huelgo de válvulas de admisión y escape | 0.008 | pulgada (0.2 mm) | motor frío y parado |
| Voltage | DC voltmeter reading | between 11 and 15 volts | volts | at 80°F (25°C) ambient temperature |
| Voltage | Voltímetro CC | 11 y 15 | voltios | temperatura ambiente de 80°F (25°C) |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Coolant | 50% water / 50% ethylene glycol antifreeze mix | Not methyl alcohol based antifreeze; antifreeze with high silicate should not be used. Distilled or soft water preferred | |||
| Coolant | Mezcla 50% agua / 50% etilenglicol (anticongelante) | Recomendado para todo el año | |||
| Engine oil | SAE 5W sencilla / SAE 5-20W múltiple | API Servicio CC/CD/CE (sencilla); API Servicio CC/CD/SF (múltiple) | below -23°C | Bajo -10°F (-23°C); puede aumentar el consumo de aceite. Nunca agregue aditivos ni aceite limpiador. | |
| Engine oil | SAE 5W single viscosity / SAE 5-20W multi-viscosity | API Service CC/CD/CE single viscosity; API Service CC/CD/CF multi-viscosity | below -23°C | Below -10°F (-23°C); some increase in oil consumption may be expected with SAE 5W and SAE 5-20W oils | |
| Engine oil | SAE 10W sencilla / SAE 10-30W múltiple | API Servicio CC/CD/CE (sencilla); API Servicio CC/CD/SF (múltiple) | -23°C to 0°C | -10 a 32°F (-23 a 0°C) | |
| Engine oil | SAE 10W single viscosity / SAE 10-30W multi-viscosity | API Service CC/CD/CE single viscosity; API Service CC/CD/CF multi-viscosity | -23°C to 0°C | -10 to 32°F (-23 to 0°C) | |
| Engine oil | SAE 30W sencilla / SAE 15-40W múltiple | API Servicio CC/CD/CE (sencilla); API Servicio CC/CD/SF (múltiple) | above 0°C | 4.0 litros | Arriba de 32°F (0°C) |
| Engine oil | SAE 30W single viscosity / SAE 15-40W multi-viscosity | API Service CC/CD/CE single viscosity; API Service CC/CD/CF multi-viscosity | above 0°C | 4.9 liters | Above 32°F (0°C). Engine capacity with new oil filter: 4.75 quarts (4.9 liters) - M773LW3(G) |
| Fuel | Diesel grado No. 1 | ASTM D975 | below 0°C | Bajo el punto de congelación y en altitudes de más de 5.500 pies (1.500 m) | |
| Fuel | Grade No. 2 diesel above freezing 32°F (0°C); Grade No. 1 below freezing and at altitudes above 5,500 ft. (1500 meters) | ASTM designation D975; low or ultra low sulphur; cetane number minimum of 45 | Do not use domestic heating oils, Class B engine, Class D domestic fuels, Class E/F/G/H industrial or marine fuels, ASTM-D975-60T No. 4-D and higher | ||
| Fuel | Diesel grado No. 2 (ASTM D975) | ASTM D975; número de cetano mínimo 45; menos del 1% de azufre (preferible menos del 0.5%) | above 0°C | Arriba de 32°F (0°C) |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Tools: Juego de galgas
Tools: feeler gauge, wrench
Tools: Bombilla de prueba CC
⚠ Escaping diesel fuel under pressure can penetrate skin; relieve pressure before disconnecting lines.
Tools: wrench, cardboard
⚠ Nunca utilice ningún aceite limpiador.
⚠ Tire el aceite de desperdicio de manera apropiada.
⚠ El apretar demasiado puede causar daño en la caja del filtro.
Tools: Llave de filtro
⚠ Ponga material protector debajo de los desarmadores para no dañar la caja de la bomba.
⚠ Mantenga a bordo un rodete y una junta de cubierta de reserva.
Tools: Alicates puntiagudos, Dos desarmadores
⚠ Overtightening can damage the filter element.
Tools: filter wrench
⚠ Close the sea-cock before working on the engine cooling system.
⚠ Do not open the filler cap when the engine is warm.
Tools: metal rod
⚠ Never put additives or flushing oil in crankcase.
⚠ Dispose of waste oil in an approved manner.
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
The Northern Lights L731 engine has an oil capacity of 4.0 liters.
The Northern Lights L731 has a displacement of 1.13 liters with 3 cylinders.
The Northern Lights L731 powers 1 generator set(s), including Northern Lights M773L.
The Northern Lights L731 oil change interval is every 200 hours.