Common Reasons a Portable Generator Won’t Start
Stale fuel, low oil shutdown, a closed fuel valve, or a dead battery. What to check when a portable generator won’t start, plus the safety rules that matter.
Portable generators tend to sit unused for months, then get needed all at once when the power goes out. That combination makes them prone to starting problems right when they matter most.
Generator safety comes first
Carbon monoxide from a generator can kill within minutes, and you can’t see or smell it.
- Never run a generator indoors, including in a garage (even with the door open), basement, shed, or crawl space.
- Run it outdoors, well away from the house, with the exhaust pointed away from doors, windows, and vents. Follow the distance in your owner’s manual.
- Have battery-powered or battery-backup CO alarms working inside the home.
- Never plug a generator into a household outlet (“backfeeding”). It can kill utility workers and neighbors and damage your home’s wiring. A home connection requires a properly installed transfer switch or interlock done by a licensed electrician.
- Let the engine cool before refueling, and store fuel away from the generator and the house.
1. Stale fuel
The most common cause. Gas left in the tank or carburetor for months can break down and leave varnish that blocks fuel flow. Drain old fuel into an approved container and refill with fresh fuel of the type your manual calls for.
2. Fuel valve or choke
Many generators have a fuel shutoff valve. It’s easy to forget to open it. Also check the choke position the manual specifies for a cold start, and the engine switch if your model has one.
3. Low oil
Most portable generators have a low-oil sensor that prevents the engine from starting or shuts it down. Check the oil on level ground. A generator sitting on a slope can also trip the sensor.
4. Spark plug
A fouled plug is a common culprit after storage. With the engine off and cool, inspect it and replace it with the specified type if needed.
5. Battery (electric-start models)
Starter batteries drain in storage. If the electric start does nothing or clicks, try the recoil start if your model has one, and charge or replace the battery.
6. Loads plugged in
Disconnect everything before starting. Starting under load can make the engine stall or struggle.
Starts but won’t produce power?
If the engine runs but there’s no power at the outlets, check the generator’s circuit breakers or reset button first. Beyond that, electrical output problems are outside basic troubleshooting. Don’t open the generator’s electrical components yourself.
Test it before you need it
Many manufacturers recommend running a stored generator periodically. Check your manual for the recommended schedule and how to do it safely. A test run in October beats finding a problem during a February ice storm.
When to call
If fresh fuel, oil, and the plug don’t get it running, or it surges, stalls, or leaks fuel, call or text Westland Small Engine Repair at (734) 400-0790. More on the generator repair page.
This article is general guidance. Always follow the owner’s manual and safety instructions for your specific generator.