Diagnosing a Lawn Mower Starting Problem

lawn mower features a single-combustion engine and parts that are highly durable. This is a house tool that takes a beating every time you mow the lawn and even when you sit outside in the elements. When your mower won’t start, the problem may be easier to diagnose and fix than you think.

Gas up

It may sound obvious, but the simplest things are often left unchecked. Open the gas tank and make sure there is gas in the tank. If there is, you may need to remove it and add new fuel or, at the very least, top it up with fresh fuel.



All lawnmowers have a filter for the engine, usually right next to the fuel tank. You may have to remove the fuel line to get to it and remove it. A dirty fuel filter will prevent fuel from circulating properly. A small pair of pliers or wrench will allow you to access the filter. Remove and wash or blow out debris with a can of air. If the filter cannot be saved, you can choose a generic filter at your local hardware store.

Another filter that is often left unchecked is the air filter. Not all lawnmowers have one of these. If your mower does, it will be located near the exhaust in a container. Remove it as you would a fuel filter and clean it in the same way.


Over time, the spark plugs can get so dirty that they can no longer spark. Spark plugs are generally visible on most lawn mowers. Remove the hose and fitting covering the end of the spark plug. A wrench may be required to remove the spark plug. Look at the end of the spark plug and if it is dirty, clean it with a brake cleaner and a wire brush. If this doesn’t do the job, buy a new spark plug. Be aware that a spark plug can become over-tightened, preventing it from firing. You can also fit a starter mower to see if yours will kick in. If so, the spark plug most likely needs cleaning and not replacement.


If your lawn mower has been left out, then old gasoline may be the cause of your problems as it remains in the carburetor. You can buy a cleaner specifically for the carburetor. Clean it well and try to start it again. If this doesn’t work, then it may be the air and gas mixture inside the carburetor. There are bolts found on the carburetor that can be adjusted to provide more air or gas mixture flow.

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