How to Fix Lawn Mower Blade Spinning But Not Cutting

I know how frustrating it is to head out on a Saturday morning to mow your lawn and find that your lawn mower blade is spinning but not cutting. Before you take your mower to a professional, check out this guide to learn a few of the common reasons why this might be happening and what you can do to fix it. Usually, it’s something pretty simple that you can take care of yourself at home with just a few simple tools. Let’s dive in.

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Mower Blade Spinning But Not Cutting (Overview)

A well-maintained lawn mower is a key tool for a healthy lawn. However, sometimes the blade may spin without actually cutting the grass. This issue can be caused by a variety of factors, including the following items:

Dull Blade
Bent Blade
Loose Blade
Clogged Deck
Struggling Engine
Wrong Cutting Height

A Closer Look at Why Your Mower Blade Spins But Doesn’t Cut

Let’s take a closer look at the six common reasons why a lawn mower blade spins but doesn’t cut even though the engine is running.

Dull Blade

Over time, the lawn mower’s blade can become dull and worn out, making it difficult to cut through grass effectively. A dull blade can result in a ragged and uneven cut and, in some cases, can leave uncut patches of grass. If the blade is dull, you will need to sharpen or replace it. One way to tell if your lawn mower blade is dull is to look at freshly cut grass blades. If the grass blades look torn, then you’ll know the blade is dull and needs sharpening. Check out my article on the best angle to sharpen a lawn mower blade to make sure your blade cuts smoothly.

Bent Blade

If your lawn mower’s blade hits a hard object, such as a rock or a tree stump, it can become bent, preventing it from cutting grass properly. A bent blade can result in an uneven cut and sometimes causes the mower to vibrate or make unusual noises. If the blade is bent, you will need to straighten or replace it. Tip over your lawn mower and check the blade’s condition.

Loose Blade

A loose blade can also lead to a lawn mower blade spinning but not cutting. If the blade is not tightly secured to the mower deck, it can wobble and not cut the grass evenly. This can result in an uneven cut or missed patches of grass. If the blade is loose, you will need to tighten or replace it. Again, tip over your lawn mower and take a closer look at the blade. If you are able to spin the blade without the center driveshaft or spindle turning, then your blade has become loose. Just remember to remove the spark plug first.

Clogged Deck

If the mower deck is clogged with grass clippings, dirt, or debris, it can prevent the blade from rotating properly and cutting the grass. This can cause the mower to become bogged down or stop the blade from spinning altogether. To fix this issue, the deck will need to be cleaned thoroughly and any debris removed. So, if you take a look under the deck, you should be able to see if the lawn mower is clogged or not. If your deck is clogged, then it’s likely that your bagger chute is as well. So head over to my article on how to prevent the bagger chute from clogging to fix and stop this issue from happening again. If you have a riding mower, check out my article on how to inspect a riding mower cutting deck.

Struggling Engine

If your mower’s engine is not running properly or is losing power, it can cause the blade to spin too slowly or not at all, which can result in poor cutting performance. An engine can struggle for a number of reasons, including old or contaminated fuel, a clogged air filter, or a faulty spark plug. To fix this issue, you will need to service the engine and replace any faulty parts. So, if your lawn mower sounds like it is struggling and can’t achieve full RPMS, then this is likely why it will not cut even though the engine is running. If you’re having engine problems, check out these articles to help you pinpoint and fix the issue:

Wrong Cutting Height

If you have your lawn mower set to the wrong cutting height, it could prevent it from cutting properly. For example, if you set your mower too low, it will scalp the grass. On the other hand, if you set it too high, it won’t cut the grass as much and might make it seem like it is not cutting the grass at all. So check that your mower’s cutting height is set to the proper height for your grass type. Here’s an article to help you figure out how to set the right cutting height on your lawn mower.