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What do I do when my lawn and garden engine has loss of power?

Loss of Power 

Small engines for power equipment, such as lawn mowers and garden tillers, are designed to run at a uniform speed. The manufacturers have calculated that the running speed will provide enough power for the implement to do its assigned task. Although these engines are relatively simple and very reliable, occasionally something will go awry and the engine will lose power. The power loss may be continuous, or may ebb and flow, making it difficult, if not impossible, for you to continue with your task. The power loss may be caused by several factors, some of which you can easily remedy.


Your power equipment engine, just like the gas engine in your personal vehicle, needs three things to run properly—air, fuel, and a spark to ignite the air and fuel mixture. If any of these elements are not supplied to the combustion chamber in the proper mixture and at the proper time, your engine will not run smoothly and may lose power. 

The carburetor is used to mix the proper amount of air and fuel together and direct the mixture into the combustion chamber. Once in the chamber, your spark plug sparks at the proper time to ignite the mixture and apply a force to the piston, which drives your mower or tiller blade. 

Incorrect amounts of air or fuel will cause the engine to run sporadically or not at all, as will a weak or improperly timed spark. An engine not getting the right amount of fuel, air, or a proper spark will exhibit a loss of power.

What to Look For

Air Filter – The air filter cleans the air before it is drawn into the carburetor and when it does its job properly, may get clogged up with debris removed from the air. A clogged air filter may not allow a sufficient amount of air into the carburetor, reducing the power of the engine. 

Fuel – Bad or dirty fuel will also cause your engine to lose power. Gas will go stale in as few as 30 days, especially fuel mixed with ethanol as it is in many areas. Ethanol attracts moisture over time and the moisture will dilute the gas. 

Fuel Filter – Your engine’s fuel system has a filter to remove dirt from the fuel before it enters the carburetor. As with the air filter, when the fuel filter does its job, it will become less efficient and may become clogged, restricting fuel flow to the engine.

Tall Grass – Trying to cut grass that is too tall will cause your mower to lose power as it tries to move through the tall grass. 

Improper Oil Level – Loss of power may also be caused by an improper level of oil in the mower or tiller. Too high a level will lead to froth introducing air into the lubrication system and reducing the ability of the oil to lubricate the moving parts. Too low an oil level will also reduce your system’s ability to provide adequate lubrication, increasing friction and putting more of a load on your engine. 

Faulty Spark Plug – A pitted or fouled spark plug will cause inconsistent ignition, and fuel, carbon, dirt and oil on the plug electrodes will also result in an inconsistent spark and loss of power.  

What to Do

If the fuel in your engine is old, it should be properly disposed of and replaced with fresh fuel. As long as you’re checking the fuel system, remove the gas cap and clean the vent in the cap. If the vent remains clogged, replace the fuel cap.

For other items, such as the air filter and the oil level, these can be check before usage and cleaned, replaced or adjusted as necessary. If your engine needs new air and fuel filters, or a new spark plug, insist on a product from a name-brand manufacturer, such as Champion. Also, make sure that whatever parts you buy are genuine, not low budget knock-offs.    

Before you attempt to cut tall grass or weeds, it may be necessary to adjust the cutting height of your mower. Instructions may be found in your owner’s manual.


Once your lawn and garden engine is back up to snuff and happily humming along at full power, you’ll wonder how you ever accomplished anything with the way the engine used to perform. 

Learn more about lawn & garden equipment maintenance products, find your part, or find where to buy your 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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