Cummins/Onan 4.0EGHAB Engine Engine

• UNIT RUNS THEN SURGES
  Cause: 1. Loose or worn spark plug lead 2. Faulty spark plug. 3. Dirty fuel filter or generator set at too steep of an angle. 4. Governor out of adjustment or lean fuel mixture.
  Fix: 1. Check spark plug lead connection. 2. Remove and clean or replace. 3. Check fuel filter and angle of generator set. 4. Contact an Onan service center.
• UNIT RUNS THEN STOPS
  Fix: Add fuel. Add oil. Reduce oil level.
• UNIT RUNS BUT SURGES
  Fix: Add fuel. Add oil. Reduce oil level.
• NO DC OUTPUT VOLTAGE
  Cause: 1. Open DC circuit breaker due to an overload.
  Fix: 1. Remove all loads, reset breaker, check for shorted battery or load defects. Do not exceed rated load specifications.
• NO AC OUTPUT VOLTAGE
  Cause: Open AC circuit breaker due to an overload
  Fix: Remove all loads, re-set circuit breaker, check tools or appliances being used for defects. Do not exceed generator set rated load specifications.
• FAILS TO CRANK (ELECTRIC START MODELS)
  Cause: Low Battery, Bad battery connection, Oil is too heavy, Load is connected
  Fix: Check battery electrolyte level and charge. Clean and tighten all battery and cable connections. Replace with lighter oil. Always disconnect load while starting.
• FAILS TO CRANK
  Cause: 1. Low battery. 2. Bad battery connection.
  Fix: 1. Check battery electrolyte level. 2. Clean and tighten all battery and cable connections.
• EXHAUSTING BLACK SMOKE
  Cause: Open DC circuit breaker due to an overload
  Fix: Remove all loads, reset circuit breaker, check for an overload or short circuit. Do not exceed generator set rated load specifications.
• ENGINE WON’T START
  Cause: 1. Fuel below genset pickup level in tank. 2. Fuel supply shutoff valve closed. 3. Remove spark plug and clean. 4. Add oil if necessary.
  Fix: 1. Add fuel. 2. Fully open fuel supply valve. 3. Replace with recommended oil. 4. Disconnect load while starting.
• ENGINE WONT START
  Cause: Loose or worn spark plug lead, Faulty spark plug, Dirty fuel filter or generator set at too steep of an angle, Governor out of adjustment or lean fuel mix
  Fix: Check spark plug lead connection. Remove and clean or replace spark plug. Check fuel filter and generator set angle. Contact an Onan service center.
• CRANKS SLOWLY (ELECTRIC START MODELS)
  Cause: Choke closed, Dirty air filter, Rich fuel mixture
  Fix: Open choke. Clean or replace air filter. Contact an Onan service center.
• CRANKS SLOWLY
  Cause: 1. Low battery. 2. Bad battery connection.
  Fix: 1. Check battery electrolyte level. 2. Clean and tighten all battery and cable connections.

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan 4.0EGHAB.