There’s nothing more frustrating than pulling the starter cord or pressing the ignition on your mower, only to be met with silence (or that dreaded sputter). Don’t worry—most mower start-up issues can be solved without a costly repair bill. This guide walks through the five most common reasons your mower might not start and, more importantly, how to fix them.
1. Old or Bad Gasoline
If your mower has been sitting idle for a while (like over the winter), chances are the gas in the tank has gone stale. Over time, gasoline can break down and become less combustible, making it difficult for your mower’s engine to ignite.
How to Fix It:
- Drain the old gasoline from the tank.
- Refill the tank with fresh, stabilized gasoline.
- If possible, add a fuel stabilizer at the end of each mowing season to prevent future issues.
Pro Tip: Adding a fuel stabilizer before storing your mower for the season can prevent stale gas issues next year.
2. Clogged Air Filter
Your mower’s engine needs a steady supply of clean air to combust fuel properly. If the air filter is clogged with dirt, grass clippings, or dust, airflow is restricted, and your engine may struggle to start.
How to Fix It:
- Locate the air filter housing (usually on the side of the engine).
- Remove the air filter and inspect it for dirt, grime, or blockages.
- Clean it if it’s washable, or replace it with a new one if it’s paper or too far gone.
Pro Tip: Keep a spare air filter on hand, especially if you mow frequently or in dusty environments. Check your mower’s manual for the right filter type.
A dirty, fouled, or worn-out spark plug can prevent your mower from starting. The spark plug is responsible for igniting the fuel-air mixture inside the engine, and if it’s not working properly, the engine won’t start.
How to Fix It:
- Use a spark plug wrench to remove the spark plug from the engine.
- Check for signs of wear, carbon buildup, or a corroded tip.
- Clean the spark plug with a wire brush or replace it if it’s damaged.
Pro Tip: Spark plugs are inexpensive and easy to replace. Check your mower’s manual to ensure you’re using the correct type.
The carburetor mixes air and fuel for combustion. If it’s clogged or dirty, that perfect mixture can’t be achieved, and your engine will struggle to start. This is especially common after extended periods of storage.
How to Fix It:
- Remove the carburetor (refer to your owner’s manual for guidance).
- Use a carburetor cleaner spray to clean out any gunk, varnish, or deposits.
- Reinstall it, making sure all connections are tight.
Pro Tip: If you’re not comfortable disassembling parts of your mower, consider using a fuel additive or carburetor cleaner spray that doesn’t require removal.
For battery-powered electric mowers and riding mowers, a dead or drained battery is one of the most common reasons for start-up failure. Batteries lose their charge over time, especially if not maintained during the off-season.
How to Fix It:
- Check the battery’s voltage using a multimeter. If it’s below the recommended voltage, it needs a charge.
- Recharge the battery using the appropriate charger for your mower’s battery type.
- If the battery won’t hold a charge, it’s time for a replacement.
Pro Tip: To keep your battery in good shape during the off-season, consider using a trickle charger or battery maintainer.
Bonus Troubleshooting Tips
If none of these common issues seem to be the problem, consider these additional troubleshooting tips:
- Check the Primer Bulb: If your mower has a primer bulb, press it several times to get fuel into the engine before starting.
- Look for Loose or Disconnected Wires: Ensure that no wires have come loose, especially in riding mowers.
- Inspect the Oil Level: Many modern mowers have a safety feature that prevents starting if the oil is too low. Check the oil level and top it off if necessary.
When to Call for Backup
Sometimes, it’s best to let the pros handle it. If you’ve tried all these steps and your mower still won’t start, visit your local independent Outdoor Power Equipment (OPE) dealer. These experts can diagnose the problem and get your mower back to peak performance quickly. Unlike big-box stores, independent dealers are specialists in repair and maintenance for all kinds of mowers.