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Engine stops unexpectedly

Why generators show "engine stops unexpectedly": 23 documented causes and brand-specific fixes, compiled across 12 manufacturers.

Fuel tank empty.

3 brands
  • Cummins/Onan: Fill with fresh fuel.; Refill.
  • Doosan: Refill. Check the ignition system. Repair or replace parts necessary.
  • generatorpartspro: Refill, Water temperature high. Add water.

Empty fuel tank.

2 brands
  • Cummins/Onan: Refill fuel tank as often as needed to prevent running out of fuel.
  • generatorpartspro: Refill.

Fuel tank empty

2 brands
  • Cummins/Onan: Fill with fresh fuel; Refill
  • Doosan: Refill

Empty fuel tank. Defective ignition system.

2 brands
  • Cummins/Onan: Refill. Check the ignition system. Re- pair or replace as needed. See that the STOP button lead is not grounded.; Refill. Check the ignition system. Repair or replace as needed. See that the STOP button lead is not grounded.
  • D.W.Onan: Refill. Check the ignition system. Repair or replace as needed. See that the STOP button lead is not grounded.

Empty fuel tank, Defective ignition system. Fuel pump failure.

2 brands
  • Cummins/Onan: Refill. Check the ignition system. Repair or replace as needed. See that the STOP button lead is not grounded.
  • Onan Electric: Refill. Check the ignition system. Repair or replace as needed. See that the STOP button lead is not grounded.

Empty fuel tank. Defective ignition system. Fuel pump failure.

2 brands
  • Garretson: Refill. Check the ignition system. Repair or replace as needed. See that the STOP button lead is not grounded. Repair or replace.
  • NEC: Refill. Check the ignition system. Repair or replace as needed. See that the STOP button lead is not grounded. Repair or replace.

Fuel tank empty. Defective ignition.

1 brand
  • Cummins/Onan: Fill with fresh fuel. Check ignition system.; Réfill. Check the ignition system. Repair or replace parts necessary.

Fuel tank empty, Fuel pump failure, High water temperature, Defective ignition

1 brand
  • Cummins/Onan: Refill, Repair or replace, See symptoms for engine overheating, Check the ignition system. Repair or replace parts necessary

Black smoky exhaust normal condition with overload.

1 brand
  • Cummins/Onan: Reduce load to within rated capacity. If smoky condition continues, stop unit and investigate.

Fuel tank empty, Transfer Pump failure, Safety switch operated (where used)

1 brand
  • Cummins/Onan: Refill, Repair or replace, Correct the overheating or lubrication failure. Press reset switch

Check the ignition system; Repair or replace parts necessary

1 brand
  • generatorpartspro: Refill; Check the ignition system; Repair or replace parts necessary

Empty fuel tank. Refill. Check the ignition system. Repair or replace as needed. See that the STOP button lead is not 5 founded. Defective ignition system. Fuel pump idilure. Repair or replace.

1 brand

Fuel tank empty, Defective ignition, Dull metallic thud if not bad may disappear after few minutes operation if bad increases with load

1 brand
  • Cummins/Onan: Refill fuel tank, Check and repair or replace parts of ignition system as necessary, Replace unless one of the next two remedies permanently corrects trouble

Out of fuel

1 brand
  • Allis-Chalmers: 1. Fill fuel tank with specified fuel and prime the fuel system. 2. Check fuel system. 3. Correct or replace affected parts. 4. Replace inoperative parts.

Restricted fuel supply

1 brand
  • Allis-Chalmers: 1. Fill fuel tank with specified fuel and prime the fuel system. 2. Check fuel system. 3. Correct or replace affected parts. 4. Replace inoperative parts.

Related fault codes

Common questions

What causes engine stops unexpectedly?

Common causes, most-reported first: Fuel tank empty.; Empty fuel tank.; Fuel tank empty; Empty fuel tank. Defective ignition system.; Empty fuel tank, Defective ignition system. Fuel pump failure.; Empty fuel tank. Defective ignition system. Fuel pump failure..