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Cummins/Onan MAJ Engine Engine

The Cummins/Onan MAJ is an engine rated at 3600 rpm. It powers generator sets from Cummins/Onan, including the 2.5MAJ.

3600 rpm
Rated speed

Engine specifications

Rated speed3600 rpm

Generator sets powered by this engine

1
Cummins/Onan 2.5MAJ

Troubleshooting

3

Symptoms & remedies

SymptomCauseRemedy
Low Oil PressureCheck the oil level. If low, add oil to bring level up to 1 /4 inch (6 mm) from the fill opening. Do not overfill. Inspect engine exterior for leaks and repair as necessary.The oil pressure switch grounds the ignition circuit if pressure drops below 8 to 10 psi (55 to 69 kPa), and causes genset shutdown.
High Engine TemperatureCheck condition and tightness of the sea water pump belt. Sea water flow at the hull exhaust outlet for a new pump should be about 1.8 gal/min (6.8 L/min) for 60 hertz gensets, and 1.5 gal/min (5.7 L/min) for 50 hertz gensets. Also check cooling system for freedom of contaminants, rust and sludge build-up, etc.The thermostat switch closes at engine temperatures over 200' F (93' C) and grounds the ignition circuit to cause genset shutdown.
High Exhaust TemperatureHigh exhaust manifold temperature is caused by failure of the sea water cooling system. Failure can be caused by a defective sea water pump, drive belt, plugged inlet filter, or a closed water valve.Sea water flow at the exhaust outlet should be as referenced in the High Engine Temperature text. Whenever a shutdown occurs, a thorough inspection of the complete exhaust system must be made by an experienced service person.

Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.

Common questions

Which generators use the Cummins/Onan MAJ engine?

The Cummins/Onan MAJ powers 1 generator set(s), including Cummins/Onan 2.5MAJ.