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Troubleshooting Lawn Mower Starting Problems

Its summer – time for yard work

The air is warmer and the grass is growing – time to break out the lawn mower. Unlike your car, your lawn mower and other lawn and garden equipment are not used regularly and the time spent sitting in storage can lead to problems with them running properly.

When you take your mower out for the first time, you may encounter a variety of situations. If you are lucky, the lawn mower will start with the first pull of the cord. Unfortunately, after months of sitting around, it is likely your lawn mower may not run smoothly, or even start at all. Before you give up, here are some things you can do to troubleshoot the problem.

Causes of engine trouble

If your engine starts but does not run smoothly or doesn’t start, the culprit could be air intake or fuel system related. The problem could be the age of the fuel in the tank, dirt or debris in the carburetor or an obstructed fuel tank vent. Other causes could be a fouled spark plug or a dirty or clogged fuel filter that restricts the amount of fuel getting to the carburetor.

Ways to keep lawn mower running graphic.

Change the gasoline

If this is the first time you have tried to start the engine since last fall, fresh fuel may be in order. Gasoline will go bad in as few as 30 days, especially when fuel is mixed with ethanol as it is in many areas. Ethanol attracts moisture and over time the moisture will dilute the gas.

If the fuel is old, it should be dumped into a container for proper disposal and fresh fuel should be added. Fuel additives are readily available wherever auto parts are sold and may be helpful in not only starting your engine, but also in cleaning out any gum or varnish deposits in your carburetor while the engine is running.

After adding new fuel, check the gas cap. In many small engines, the gas cap also has a vent that serves as the fuel tank ventilation. In order to work properly and supply a sufficient amount of fuel to the carburetor, the vent must be open and free of any debris.

Change gasoline in lawn mower graphic.

Check the air filter

The job of the air filter is to remove dirt and debris from the air before it enters your engine. The filter may become clogged and not allow a sufficient amount of air into the engine for it to run smoothly. If the filter is dirty, it should be replaced.

Check lawn mower air filter graphic.

Examine the spark plug

A dirty or fouled spark plug can cause your lawn mower to not start. It can also work itself loose, causing issues. If the spark plug appears to be seated correctly but the engine doesn’t start, a new one may be in order. For a few dollars, this easy fix can get your small engine working again. Be sure to use the correct replacement spark plug designed for your lawn mower.

Check for bad lawn mower spark plug graphic.

Check the oil

Check the amount, color and consistency of the oil. If it appears dark black, change it. If the oil level is low, add the proper oil, identified by your owner’s manual, to the engine – but be careful not to overfill it!

Check and change lawn mower oil graphic.

Look at the Fuel Filter

The fuel filter keeps dirt and contaminants in the fuel from getting into the carburetor. If it becomes clogged, it can prevent a sufficient amount of fuel from passing into the combustion chamber, preventing your engine from starting. Check the fuel filter, replace it if it is dirty or clogged.

Check fuel filter in lawn mower graphic.

I’m still having issues with my mower – what should I do?

If you are still having problems, it might be time to take it to a small engine repair shop to have a mechanic look at it. With their expertise, they’ll get to the bottom of the problem in no time.

Learn more about Champion parts, find your car part, or find where to buy your auto part today.

The content contained in this article is for entertainment and informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.

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