A generator that fails in an outage is worse than none at all, because you were counting on it. Most failures trace back to a short list of causes.
What usually goes wrong
Won’t start
A weak battery is the top cause. Corroded terminals and fault codes follow.
Starts, then shuts down
Low oil, overheating, overspeed, or low gas pressure with other appliances on.
Won’t transfer
Control wiring, a failed contactor or a controller setting.
Overloads with AC on
Undersized unit, failed load module, or AC without a soft starter.
Skips its self-test
Clock reset after a battery change, or an active alert.
Pests and corrosion
Fire ants and rodents nest inside. Humidity eats connectors.
Safe checks before you call
- Read the controller screen or app and write down any alarm code
- Make sure it’s set to Auto, not Off or Manual
- Check the generator’s main breaker
- Confirm the gas valve is open and other gas appliances work
- Look for ant mounds or chewed wires, but don’t open electrical panels
Generators make carbon monoxide and high voltage. Never run a portable generator in a garage, and leave transfer switch and internal wiring work to a licensed pro.
Warranty first
Most new generators carry manufacturer warranties that often require a factory-authorized service dealer and maintenance records. Check your paperwork before you book a repair.
If yours is old and failing often, read about replacement. Regular maintenance heads off most of these problems.
Need a technician?
Tell us what’s happening and we’ll match you with a local repair pro.
Common questions
Why won’t my generator start?
Usually a weak battery, a tripped breaker, low oil shutdown, a fault code or a gas supply problem. Check the controller for alerts first.
Can any technician fix my Generac or Kohler?
Many independent techs service several brands, but warranty work usually needs a factory-authorized dealer.