Other outdoor power

Generator won't start

Generators fail to start for the same reasons as other small gas engines: stale fuel, a fouled plug, or a low-oil safety shutoff preventing ignition.

Difficulty
Easy
Time
20–40 minutes
DIY cost
$10–$30
Pro cost
$90–$180

Symptoms

  • Pull cord or electric start does nothing
  • Engine turns over but doesn't fire
  • Started fine last season, won't start now
  • Fuel valve or choke set incorrectly

Likely causes

  • CommonLow oil triggering the automatic shutoffMost generators won't start if oil is below the minimum level.
  • CommonStale fuelOld gas breaks down and clogs the carburetor.
  • CommonFouled spark plugCarbon buildup prevents reliable spark.
  • PossibleFuel valve closed or choke misadjustedSimple switch positions are often overlooked.
  • PossibleDead battery on electric-start modelsBatteries discharge during storage.

What to do

  1. Check the oil level first since low oil blocks starting on most models.
  2. Open the fuel valve and set the choke according to engine temperature.
  3. Drain stale fuel and refill with fresh gasoline if it's been stored for months.
  4. Pull the spark plug and check for fouling; clean or replace it.
  5. For electric-start models, check or charge the battery.
  6. Check the air filter and clean or replace if dirty.
  7. If it still won't start, the carburetor may need professional cleaning.

Tools and parts

  • Spark plug socket
  • Fresh gasoline
  • Engine oil
Generator engine oilSearch: “small engine oil for generator”
Spark plugSearch: “portable generator spark plug”

When to call a pro

A small-engine shop can service the carburetor or test the ignition if basic maintenance doesn't get it running.

Safety

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.