Frustrated man sitting next to a lawn mower that loses power when cutting.

Lawn Mower Loses Power When Cutting! Possible Causes And Solutions

6 minutes

You depend on your lawn mower to keep your lawn’s good look and shape. But sometimes your lawn mower loses power when cutting. What do you do? We’re here to help with the most likely causes and the solutions that can help.

Possible Causes For Why Your Lawn Mower Loses Power When Cutting

Unfortunately, there can be several reasons why your lawn mower loses power when cutting. We’ll go through each in detail. Before doing so, please know that if you don’t feel comfortable handling these yourself, we recommend getting the help of a professional. Safety is more important than anything else, after all.

Clogged Air Filter

Closeup of an air filter on a lawn mower.

Lawn mower air filters keep dust and other things from getting into the lawn mower’s engine. These keep the lawn mower running efficiently and extend your engine’s life. If you haven’t replaced the air filter in a long time, it’s possible it’s clogged and air can’t get to the engine any longer, which can shut it off.

Dirty Carburetor

Closeup of a lawn mower carburetor.

Carburetors are one of the most important parts of an engine. They deliver the air and vaporized fuel mixture to the engine. But when the inside piping of the carburetor gets dirty, it cannot deliver the needed air and fuel to the engine. This can result in a loss of power.

Cleaning the carburetors will usually solve this problem. If it doesn’t, we recommend getting a professional to take a look.

Bad Spark Plug

Closeup of a lawn mower spark plug, which can be a cause for why a lawn mower loses power when cutting.

A spark plug is considered the heart of the engine. It provides the spark that causes the air/fuel mixture to explode. This creates power for your engine.

Over time, spark plugs can wear down or suffer from oil buildup. What this means is that sometimes they won’t produce that spark, which can turn your engine off. Replacing or cleaning the spark plugs will solve the issues here.

Dirty Fuel

Someone pouring gas into a lawn mower.

Clean fuel is required for an engine to run correctly. There will not be a good burn if the fuel is contaminated in any way. Sometimes, this can even cause parts to become damaged or explode.

There are different reasons for why fuel becomes dirty. For example, you leave your lawn mower in the rain, water can end up in the tank. If you leave a gas canister open, dirt can get into the fuel.

If you think dirty fuel might be the issue, first, make sure the lawn mower is off. Then, try emptying the tank and cleaning it. If you’re not comfortable doing this, a professional can always help.

Blocked Muffler

Closeup of a muffler, which can be a cause for why a lawn mower loses power when cutting.

After each combustion, your engine produces various gases. These gases are not good for combustion. So, the burned gas needs to get out before the next air and fuel mixture gets inside.

A muffler allows those gases to escape. If the muffler becomes blocked with dirt and debris, these gases have nowhere to go. In that case, they might end up in the engine. A quick check and cleaning of your muffler might just be the solution you need to get your lawn mower up and running.

Low Engine Oil Level

Person checking the oil level in their lawn mower.

There can be different oil levels in the lawn mower, resulting in an unhealthy state for the engine. This can create sudden power loss while mowing the lawn.

Engine oil helps to keep the lawn mower parts lubricated. If there is a lack of oil inside, the lubrication system will fail due to extensive heat generation. Friction is a major enemy of the engine’s parts.

In extreme cases, the engine parts can melt and become welded together if you do not solve the problem immediately after figuring it out. If you wait too long, you may have to replace the engine altogether. 

Clogged Cutting Deck

Closeup of a lawn mower's front, including the cutting deck.

A clogged cutting deck can put extra pressure on the engine, which may result in a loss of power.

There can be several causes for a clogged cutting deck. For example, if you have cut wet grasses lately, there can be a chance it is the cause of the blockage. Wet grasses get stuck together easily and create a blockage on the rotational path of the mower blade. They also can get to the blade and shaft connection and stop the blade from rotating.

If you think a clogged cutting deck is your issue, it’s time to give it a good clean.

What If An Electric Lawn Mower Loses Power When Cutting?

If the power loss happens with an electric lawn mower, the problem may be due to the battery.

A battery become worn down after long-time use. So, the battery can not deliver enough power to the motor as it can not hold enough of a charge anymore. In this case, you’ll need to get a replacement battery.

What If It’s Some Other Problem That’s Causing The Lawn Mower To Lose Power When Cutting?

The problems from the above discussion are the most common ones. But sometimes, you may be dealing with a different problem. You should take your mower to a professional at your nearest repair shop if it happens. They will be able to help you.

Remember, if you can not identify the problem, do not keep using the mower.

In Conclusion: Lawn Mower Loses Power When Cutting

There’s nothing more frustrating than losing power halfway through mowing your lawn. Thankfully, now you’ll know exactly how to deal with a lawn mower when it loses power when cutting. What are your thoughts on this though? Any issues we missed? Let us know in the comments below!

Todd L Miles
Lawn Mowers Enthusiast
I started "Landscape and Lawns Care" to provide clients with lawn care with better service, better products and, most importantly, better ethics. My promise to every customer is to give the greenest grass possible while controlling weeds, insects, and diseases! The most important thing is that I strive to always do the right thing for you, your lawn and your wallet!