5 Reasons Why Lawn Mower Losing Power When Cutting | Fix It Now!

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So it goes like this-You finally decide to make your lawn neat and tidy, but when you start cutting grass, the lawn mower keeps losing power- maybe this or something similar to this has brought you here today?

Whatever the case may be, the lawn mower losing power every other second has to be one of the most annoying things! But don’t worry; we got you covered. There can be many reasons behind it, starting from a dirty air filter to poor battery health.

Today we will discuss everything you need to know about a lawn mower’s operation and the possible reasons why it might be losing power whenever you are trying to cut the grass.

Understanding The Operation of a Lawn Mower Engine

Before jumping straight into diagnosing the issues, you need to know the basics of how a lawn mower engine operates. Having the knowledge of the fundamentals of a lawn mower engine comes in handy if the problem is minute and can be fixed without professional help.

Here’s the list of engine parts you need to know about if you want to understand the operations of a lawn mower engine. These are for a non-electric lawn mower.

  • Piston
  • Spark plug
  • Carburetor
  • Cylinder
  • Crankshaft
  • Fuel tank
  • Air filter
  • Cooling system
  • Oil system
  • Exhaust system
  • Governor

This engine type starts by drawing fuel from the fuel tank and cleaning air through the air filter for combustion. The carburetor helps here to mix the right ratio of air and fuel, and if you have some of the latest models, you might have fuel injectors instead of it.

Once the air and fuel are mixed, it goes to the cylinder (combustion chamber), and the piston starts moving downwards. It compresses the mixture and makes it combustible. Inside the cylinder is the spark plug which generates an electric spark and ignites the compressed fluid.

The ignited air-fuel mixture creates controlled explosions that give the crankshaft the power to move, and the crankshaft then turns the linear up and motion into rotations.

While all this is happening, the engine also does a cooling and lubricating action to keep the moving frictionless. Lastly, the gases produced in the combustion are exhausted through an exhaust system.

Now if you have an electric lawn mower, here are the engine parts you need to identify and understand.

  • Electric engine
  • Power source
  • Control system
  • Cutting blades
  • Grass collection system

You will see that compared to a traditional fuel lawn mower, an electric one is way less complicated to understand. But sadly, that also means you have very little room to fix the problems yourself.

If an electric mower stops working, it can be due to only a few major reasons, such as engine breakdown, power cuts, or damaged wiring due to overheating.

Other Causes of a Lawn Mower Losing Power When Cutting

Here are some probable reasons your mower might stop working while cutting grass.

1. You are Making the Mower Overwork

You are Making the Mower Overwork

Every mower has its capacity, and while using it, you should keep that in mind. If you put too much load on your mower and make it overwork, sooner or later, it will start dysfunctioning.

Since overworking causes overheating, most of the time, it affects the engine and wiring in it, so it can increase the chances of it closing power. So to avoid that, if you don’t have a heavy-duty mower.

  • Avoid cutting very thick and tall grass
  • Don’t run it over excessive grass and dirt buildup
  • Don’t use too much ground speed

Also, make sure you are lubricating the mower from time to time so that there is less friction and less heat is generated.

2. Air Filter is Dirty

Air Filter is Dirty

Air filters are crucial for gas lawnmowers. If you are using an electric one, this won’t be a problem for you since they don’t have an air filter.

But for gas lawnmowers, if the air filter is blocked, the computing process won’t happen. Therefore the engine won’t have the power to run, causing it to lose power again and again.

So check the air filter for any dirt and debris buildup. If you find any, simply take it out and tap it gently against a hard surface, and it should get clear. If the debris is too stubborn to remove, you can use a vacuum cleaner to suck the dirt out of the filter.

If the dirt is oily and sticky, soak the filter in soap water and give it a gentle scrub. Don’t forget to dry it thoroughly before putting it back in.

3. Using Low-Quality Fuel

Using Low-Quality Fuel

In the case of gas lawnmowers, it is often a significant issue that causes the engine to shut down frequently. If you are using low-quality or bad fuel in your lawn mower, it starts building up gummy deposits which then clog the carburetor, causing the engine to lose power.

4. Dirty Spark Plug

Dirty Spark Plug

If you are using quite an old lawn mower, chances are that the spark plug has gone faulty. It helps in igniting the fuel, so if it stops working, the mower engine will not get power. There’s no such way to repair a spark plug, so you’ll be required to replace it with a new one.

5. Electrical Problem

Electrical Problem

If the heating exceeds a certain limit, there’s a high chance of wire meltdowns and short circuits. This can be a problem for your electric mower to get proper power. Besides, if you are using wireless battery-operated mowers, then the battery health can be a reason, too, for such abrupt power shortages.


How many years do electric lawnmowers last?

Good quality electric lawnmowers can last anywhere between 8 to 10 years with regular use and good maintenance. However, factors like overworking or lack of cleaning can significantly reduce the lifespan of your mower.

What type of land mowers are best for large acres of land?

Good quality electric lawnmowers can last anywhere between 8 to 10 years with regular use and good maintenance. However, factors like overworking or lack of cleaning can significantly reduce the lifespan of your mower.

How do I choose the right type of lawn mower?

If you have a medium to small size yard, you should go for a push-back mower or a mower with at least a 14 to 16-hp engine and a mowing deck of 38 inches. However, if you have a yard that is larger than three acres, then you can go for a zero-turn rider garden mower that has at least an 18-hp engine and a mowing deck of 44-54 inches.


Just like us, machines also have their limitations, so if you want to save your lawn mower from breaking down or its engine losing power, ensure you are not overworking it. Besides that, you also need to ensure that you are cleaning and doing frequent maintenance of the machine. It will help it run smoothly and will save you from having a half-cut lawn!

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