Lawn Mower Won’t Start
Spring is here, flowers are blooming, and the grass is growing. You’re ready to mow the lawn, but your mower won’t start. Why?
Here are the most common things to check and what to do about it:
1. Check the Fuel
Start with the basics. Make sure there’s fuel in the tank.
If there is, think about how old it is. Gas that’s been sitting for more than 30 days can go bad and prevent your mower from starting.
- Drain old fuel and refill with fresh gasoline
- After refilling, it may take a few pulls to cycle the new fuel through
2. Check the Battery
If your mower uses a battery, take a moment to check its condition.
- Look for corrosion on the terminals
- Clean any corrosion with baking soda and water, then dry thoroughly
- Make sure all connections are tight
- Recharge or replace the battery if it’s weak
3. Inspect the Spark Plug
The spark plug is essential for ignition.
- Remove the plug and check for buildup or damage
- Clean it if dirty, or replace it if worn
- Reinstall it securely before trying again
4. Check the Air Filter
A clogged air filter can restrict airflow and prevent the engine from starting.
- Remove the filter
- Foam filter: wash, dry completely, lightly oil, and reinstall
- Paper filter: tap clean or replace if heavily soiled
5. Check the Fuel Cap Vent
A blocked vent can prevent proper fuel flow.
- Remove the cap and check for debris
- Clean the vent to allow airflow
- Replace the cap if needed
6. Inspect the Fuel Line and Filter
Fuel needs to flow freely to the engine.
- Look for cracks, leaks, or blockages
- Clean or replace the line or filter if fuel flow is restricted
7. Clean the Carburetor
Old fuel can leave residue that clogs the carburetor.
- Use carburetor cleaner to remove buildup
- If heavily clogged, a more thorough cleaning may be needed
8. Clear the Mower Deck
Built-up grass and debris can interfere with operation.
- Turn the mower off and tip it safely
- Remove packed grass from underneath
- Make sure the deck is clear before restarting
9. Check Safety Features
Most mowers won’t start unless safety controls are engaged.
- Ensure the handle, brake, or seat switch is fully engaged
- Check for damaged or stuck cables
10. Inspect for Internal Damage
If your mower has hit something hard, internal parts may be affected.
- A damaged flywheel key can prevent the engine from starting
- This may require part replacement
Photo by Garylittlewood; https://creativecommons.org/licenses/by-sa/4.0/, image altered.