If your lawn mower won’t start, you’re not alone. Few things are more frustrating than gearing up for yardwork only to find your mower dead silent after a few pulls or button presses. The good news? Most starting problems can be fixed at home with a bit of patience, some basic tools, and a little know-how. This easy-to-follow guide covers the most common reasons a mower refuses to start and the steps you can take to get it running again—no expensive repairman needed.
Quick Picks: Common Reasons Your Lawn Mower Won’t Start
- Old or Bad Gasoline: Fuel left in the tank over winter or for long periods can go stale and prevent starting.
- Clogged Air Filter: A dirty air filter restricts airflow, choking the engine.
- Faulty Spark Plug: Worn, fouled, or damaged spark plugs won’t ignite the fuel properly.
- Dead Battery (Electric Start): For push-button or key start models, a drained battery means no crank.
- Blocked Carburetor: Old fuel can gum up the carburetor, stopping fuel from reaching the engine.
- Safety Switch or Cable Issues: Mowers won’t start if the safety bar isn’t engaged or the switch/cable is faulty.
Buyer’s Guide: What You’ll Need for Basic Troubleshooting
- Socket Wrench Set – For removing spark plugs or bolts.
- Fresh Gasoline – Always use new, clean fuel for best results.
- Replacement Air Filter – Paper or foam, depending on your mower.
- New Spark Plug – The right size for your model.
- Carburetor Cleaner Spray – For dissolving fuel deposits.
- Battery Charger – For electric start mowers.
- Work Gloves & Eye Protection – For safety while working on machinery.
Step-By-Step Troubleshooting: How to Fix a Lawn Mower That Will Not Start
1. Check the Basics First
- Is there fuel in the tank? It sounds simple, but sometimes the obvious is overlooked.
- Is the safety lever or bar engaged? Most mowers have a bail bar you must hold down. Check that all safety switches are working.
- Is the spark plug wire attached? Make sure the rubber boot is firmly on the spark plug.
2. Replace Old or Bad Gasoline
- Empty the tank using a siphon or by tilting the mower (with care).
- Fill with fresh, clean gasoline.
- If your mower has a fuel shut-off valve, open it.
- Try starting again—sometimes, that’s all it takes.
3. Inspect and Clean or Replace the Air Filter
- Remove the air filter cover (usually a screw or clip).
- Take out the air filter. If it’s dirty, tap out debris or replace it with a new one.
- Foam filters can be rinsed and dried; paper ones should be replaced if clogged.
- Reinstall and try starting again.
4. Check and Replace the Spark Plug
- Remove the spark plug wire and use a socket wrench to unscrew the plug.
- Inspect for corrosion, carbon build-up, or cracks.
- Clean with a wire brush if only lightly fouled; otherwise, replace it.
- Make sure the spark plug gap is correct (see your mower manual).
- Install the plug, attach the wire, and try starting the mower.
5. Examine the Carburetor
- If the mower still won’t start, the carburetor might be clogged with old fuel residue.
- Spray carburetor cleaner into the carburetor intake (behind the air filter).
- Try to start the mower. If it briefly runs and dies, the carb may need a deeper cleaning or rebuild.
- Remove the carburetor and clean all jets and bowls if you’re comfortable (or take to a repair shop).
6. Test the Battery (For Electric Start Models)
- If your mower has a key or button start, test the battery with a charger or multimeter.
- Charge if low, or replace if it’s no longer holding a charge.
- Check all connections for corrosion and clean as needed.
7. Inspect Cables and Safety Switches
- Ensure all control cables are intact and moving freely.
- Check for frayed wires or loose connections.
- If a safety switch fails, the mower won’t start. Replacement is usually straightforward.
Comparison Table: Quick Solutions for a Mower That Won’t Start
| Problem | Solution | Difficulty | Parts Needed |
|---|---|---|---|
| Old Gas | Replace with fresh fuel | Easy | New gasoline |
| Dirty Air Filter | Clean or replace | Easy | New filter (if needed) |
| Bad Spark Plug | Clean or replace plug | Easy | Spark plug |
| Clogged Carburetor | Spray cleaner or rebuild | Medium | Cleaner, kit (optional) |
| Dead Battery | Charge or replace battery | Easy | Battery, charger |
| Safety Switch/Cable Fault | Inspect and repair | Easy-Medium | Replacement cable/switch |
Frequently Asked Questions
Why does my lawn mower click but not start?
This is often a battery or starter issue in electric models. For gas models, it may be a stuck starter or faulty switch.
How often should I change my lawn mower’s spark plug?
Once per mowing season is usually sufficient, or more often if the mower is used heavily.
How do I prevent starting problems in the future?
- Always use fresh fuel and add a stabilizer if storing for winter.
- Change the oil, air filter, and spark plug at least once a year.
- Clean the mower deck and keep cables and switches in good shape.
Is it worth fixing an old lawn mower, or should I buy a new one?
If a basic tune-up doesn’t solve it and repairs are extensive (like engine replacement), it might be time to invest in a new mower, especially if your current model is over 10 years old.
Can I use starting fluid to get my mower running?
In a pinch, a small shot of starting fluid can help, but repeated use means the underlying problem needs to be fixed (usually the carburetor or spark plug).
Conclusion
Getting a lawn mower that won’t start up and running again is usually a matter of checking the basics: fuel, air, spark, and safety systems. With the step-by-step approach above, you can often solve the problem in minutes and get back to keeping your yard neat and healthy. Routine maintenance keeps small problems from becoming big ones, so keep an eye on fuel quality, filters, and spark plugs, and your mower will serve you season after season.
Need to replace your mower? Check out the top-rated models and upgrade for easier, faster mowing next time you’re in the yard.