What homeowners usually notice
- The standby generator did not come on during an outage, or it cranks but will not run
- The controller shows an alarm, warning light or error message
- A portable generator pulls or cranks but never catches
- The generator runs, but the house still has no power
What to do right now
- Never run any generator indoors, in a garage, basement or near windows and doors; carbon monoxide can kill
- For a standby unit, read and write down the alarm or message on the controller
- Make sure the controller is set to auto (not off or manual) and the generator's own breaker is on
- For a portable, check fuel level, fuel valve, choke setting and the oil level
- If you smell gas near the unit or a gas line, leave the area and call the gas provider or 911
Likely causes
Weak or dead battery
A standby generator's starter battery is a common failure, especially after hot Alabama summers. A clicking sound or slow crank is a typical sign.
Fuel supply problems
A closed valve, a low propane tank, stale gasoline in a portable, or a clogged fuel filter can all prevent starting.
Controller alarm or lockout
Low oil, overcrank, overspeed and other alarms shut the unit down and keep it off until the cause is fixed and the alarm cleared.
Controller left off or in manual
After maintenance or a test, the controller may have been left in a mode that keeps it from starting automatically.
Transfer switch or wiring fault
If the generator runs but the house stays dark, the transfer switch, its controls or the wiring between them may have failed.
Safe checks you can make
- Note the exact alarm text or blinking light code shown on the standby controller
- Listen when it tries to start: clicking, slow cranking or no sound at all each point somewhere different
- Check whether the generator's circuit breaker is on and the fuel valve is open
Leave outlet covers, switch plates and the panel cover in place. Noting what you see and hear is enough; testing inside boxes belongs to an electrician.
Is this something you can fix yourself?
Several checks are safe and often solve it: setting the controller back to auto, turning the generator breaker on, opening a closed fuel valve, refilling a portable with fresh fuel and adding oil to the correct level. Clearing an alarm per the owner's manual is fine once you know what caused it. Beyond that, engine, battery charging, fuel system and controller repairs belong to a manufacturer-authorized servicer for your brand. If the engine runs fine but power never reaches the house, or a portable is connected through an inlet box and interlock or transfer switch that seems to fail, that is electrical work for a licensed electrician. Never backfeed a house through a dryer outlet or with a double-ended cord.
When professional help is the right call
- The generator runs but the transfer switch never shifts the house to generator power
- Breakers in the transfer switch or generator trip repeatedly
- Burnt smell or scorch marks at the transfer switch, inlet box or wiring
- The same alarm keeps returning after you clear it
- The unit was flooded, hit by a limb or otherwise damaged
Safety first. Shut the unit down and stay away if you smell gas, see fuel leaking, notice smoke or hear grinding. A generator that has been underwater should not be started until inspected. Carbon monoxide alarm sounding? Get everyone outside to fresh air and call 911. Keep portable units at least as far from the house as the owner's manual says, with the exhaust pointed away.
What an electrician typically checks
When the engine is healthy but power does not reach the house, an electrician can test the transfer switch, check control wiring between the generator and switch, check breakers and connections for heat damage, and verify the utility and generator sides are properly isolated. For portables, they can install or repair an inlet box with an interlock or a manual transfer switch so the house is fed safely.
If you are thinking about upgrading, the pages on generator repair and whole-home generators cover what that work involves, and the home generator installation guide explains sizing and transfer switch options.
Keeping it from coming back
Let the standby unit run its exercise cycle and glance at the controller now and then. Keep the area clear of leaves and vegetation, and schedule routine maintenance with an authorized servicer. For a portable, use fresh or stabilized fuel, run it for a few minutes every month or two, and store it dry. Before storm season, confirm the transfer equipment works so you are not testing it in the dark.