Top Reasons Why Your Lawn Mower Won’t Start (and Solutions for Each Problem)

The weather’s just right to start cutting the grass, but there’s just one bit of a problem – your lawn mower won’t start! When this happens, what are you supposed to do? Before you begin panicking and think about buying a brand new lawn mower, you might want to check out these possible causes of the problem. Who knows, you might get your lawn mower working like brand new again by applying these tips to solving potential issues.

Inspect the Spark Plug

If the problem has nothing to do with the air filter (supposing you have just cleaned it a few days ago), then you might want to inspect the spark plug by removing it. Check if this part is wet, since that’s one of the reasons why the engine fails to start. Make sure you clean it first using a carburetor cleaner instead of simply brushing away dirt with compressed air. When there’s oil residue in the spark plug, you need to use a special type of solvent to clean it well.

After cleaning, let the spark plug dry thoroughly before you try starting the engine again. If it starts working, then it was indeed the spark plug that caused the problem. However, if nothing works, then there might be another reason that needs to be addressed.

If the problem lies in a faulty spark plug, then you should check the owner’s manual for information about the right replacement part to buy. Make it a point to purchase only the recommended spark plug model since failure to do so can lead to irreversible engine problems.

When replacing a spark plug, be sure to allow the engine to cool first before removing the boot and wire from the spark plug. You may use a wrench in removing the old spark plug, and install the new one by tightening it carefully onto its cylinder head. Never over-tighten it to prevent damages. Once installed, put back the boot and wire and before starting the engine.

Check for Gas Supply at the Carburetor Bowl

Lawn Mower Won't Start - Northside Tool Rental

It’s impossible for the engine to get gas when there is a clog in the fuel filter, or when the carburetor inlet needle is plugged. So, consider removing the fuel line found at the carburetor to check the filter. If you notice that the gas supply is still sufficient, then the filter is probably clogged. Hence, you will have to check the tank’s interior and remove any debris when necessary to enable the proper flow of gas.

If you notice that gas gets to the carburetor, then you have to check for fuel in the bowl. Use a C-clamp to inspect the fuel line before removing the bowl. In case the bowl is already empty, then it may be due to a stuck seat and inlet needle. Don’t worry – these parts are quite cheap and replaceable. Just be sure you inspect the other areas of the carburetor’s interior parts since any hint of corrosion plainly means you will have to replace the whole thing.

Make Sure The Jet Isn’t Clogged

Another reason why lawn mowers don’t start is a clog in the main jet. Naturally, you will have to clean this part by removing any debris or dirt stuck in it. A spray carburetor cleaner is recommended for cleaning the jet since it can effectively strip off particles that have clogged this part. Afterwards, start the engine again, and it should work perfectly if the problem was related to debris blocking the main jet.

Fuel Issues

If you were able to start the engine, but it begins to stall out after a while, then the issue may be related to the fuel. This usually happens if you haven’t used the lawn mower for months, so you need to freshen the fuel that has been sitting around in the unit for a long period. Remove the old fuel and add new gas. It should start working again once the fuel has been replaced.

Other Possible Causes of Engine Not Starting

Aside from these common reasons why lawn mowers fail to start, you may investigate on other issues and resolve them accordingly. If you notice that the engine still doesn’t start even when the blade can rotate or you can pull on the cord perfectly well, then a damaged clutch or starter mechanism may be the culprit. You may have to replace these parts or consult a professional who can resolve these issues.

You may also notice that the engine may crank, yet it can’t catch and perform as expected. A lack of response in the key or button can also be common problems, and this is caused by a weak or dead battery. It may also be due to a poor starter motor or connection, which may be checked by a professional. Lastly, even if you can find the motor spinning, yet it fails to engage the engine, the gear is likely to be broken.

When you have some concerns about pulling the cord or being unable to do so, it is possible that a clump of grass is stuck between the deck and blade. This is quite a simple problem, since all you need to do is remove the clog. If you have already unclogged these areas, but the engine still doesn’t start, maybe the unit has a serious damage in its interior parts. With some cheap lawn mowers, you need to engage the safety interlock to before you can activate the ignition system and enable the unit to start.

Keeping Your Lawn Mower in Good Condition

To make sure that your lawn mower is always at its best condition, you need to keep it well-maintained. In fact, poor maintenance is often the cause of most problems with the unit, so you should take the time to clean its parts and make sure that every component is working as expected. Consider buying tune-up products such as fuel stabilizer, carburetor cleaner and replacement spark plugs suitable for your engine model. Periodic engine tune-up will not only enhance the engine’s performance, but it can also prolong the life and quality of the equipment.