Things to Try When Your Mower Won’t Start

You’ve used your mower all season, but when you go to mow this time, it just won’t start. Now what? Before you start shopping for new mowers, there are a few things you should try to get your mower running again.

Check the Oil

Most small engines sold today have a float in the crankcase connected to the ignition system. If the oil level gets too low, it cuts the ignition. This keeps a lack of lubrication from damaging the engine.

Make sure you’re reading the oil level correctly. If the dipstick pushes into the filler neck, it must be fully inserted to get an accurate reading. Dipsticks in Hondas must be read with the dipstick inserted but not threaded into the filler neck. For other engines, check the owner’s manual. Measurement methods aren’t consistent, even within engine families.

Oil burnoff is normal, especially at high temperatures. Check your owner’s manual for oil recommendations. Most manufacturers suggest using a heavier weight oil or a full synthetic oil for use above 90°F.


Modern fuel goes stale quickly. Always use fuel that is less than 30 days old, or less than 90 days old if it was treated with a stabilizer. Fuel-injected engines are less sensitive to stale fuel, but manufacturers still recommend using fresh gas. If the engine was stored for a long time with fuel in it, you may need to take it apart and clean off the deposits in the carburetor, fuel line, and tank. 

When you tilt the engine, always keep the carburetor pointed up. Otherwise, you will flood the engine. If this happens, you need to turn the engine over a few times. This gets the excess gas out of the combustion chamber, so the engine can start.


A clogged filter puts a strain on the engine and could throw off the air/fuel ratio. To loosen dirt on paper filters, tap them against a hard surface. Foam filters should be washed in soap and water. Wipe out the air box to remove any dirt buildup. If your engine has a vortex filter box, clean it thoroughly. These systems remove most of the dirt before it reaches the filter, so they get dirty quickly.

Some foam filters need to be oiled, while others don’t. Check your owner’s manual for instructions. Always use clean oil.


If you don’t have a good spark, the engine can’t ignite the fuel. Check the plug wires for damage, and make sure the connections are secure. Remove the spark plug and inspect the electrode. If the plug is fouled or damaged, replace it. Don’t try to sand off deposits: you could end up with grit inside the engine. Check the electrode gap, and make sure it’s within specifications.

Do you think you have a faulty coil? You can test it by removing the spark plug and plugging it into the plug wire. Hold the plug so that the electrode is against a metal part of the engine, then pull the starter. If the ignition system is working, you should see a spark between the electrodes.

Need Something for Your Mower?

Shank’s Lawn Equipment is an authorized service center for most engine brands, including Honda, Kawasaki, Kohler, Vanguard, and Briggs & Stratton. We also carry a wide range of residential and commercial mowers, including Exmark, Scag, and Cub Cadet. Visit us at 4900 Molly Pitcher Highway in Chambersburg, PA. If you need parts or accessories, order online at We ship across the United States and Canada.

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