Why Does My Zero Turn Mower Leave A Strip Of Grass?

It can be pretty frustrating to finish mowing the lawn only to find strips of glass randomly scattered. A zero-turn mower is an expensive investment, and you’d expect it to work perfectly most of the time.

There may be a lot of reasons your zero turn mower is leaving uneven cuts. The blades may be bent for one, which is the most common reason. Alternatively, the tire pressure may be lower than average.

In all cases, the best thing you can do is realize the problem as soon as possible and work on solving it. You’ll need to be aware of the common issues that may cause uneven cuts. Here are reasons your zero turn mower is leaving a strip of grass.

Reason 1: The Blades Are in a Bad Shape

The uneven cuts you’re getting may be that your blades are in bad shape, both literally and figuratively. Your blades may be in bad shape literally if they’re bent. In that case, they’ll definitely leave some strips of grass and uneven cuts on your lawn.

Your blades may get bent for a lot of reasons. For example, you may have hit a rock accidentally while mowing.

On the other hand, if they’re dull or scratched, you’ll get the same result. Worn blades won’t cause enough airflow under the mower’s deck. As a result, the grass won’t be appropriately lifted, and some strips will be left.

To know for sure whether your blade is dull, take a look at the sail. If it’s thinner than the rest of the blade, it’s your cue to sharpen or replace it. You should replace it if the sail is already too thin for sharpening it multiple times.

Reason 2: The Blades Are Unbalanced

If a blade’s side carries more weight than the other side, it’ll be unbalanced and will likely lead to uneven cuts. This usually happens when you accidentally sharpen one side more than the other.

It can also happen when the dirt accumulates on one side more than the other.

To know for sure that that’s the reason for the uneven cuts you’re receiving, you can buy a blade balancer. However, it’s better to know from early on to replace the blades if they need it because unbalanced blades may cause the spindle housing to get damaged.

Reason 3: The Tire Pressure Is Low

It happens often that one tire’s pressure gets lower than the other. Or, all the tires may have lower pressure than they should. In this case, that’ll likely be why you’re getting uneven cuts from your zero-turn mower.

The reason is simple. When one tire has lower pressure than the other, the deck will lean towards it, which will cause the mower to be unbalanced when cutting your grass.

Luckily for you, the solution is simple. All you have to do is inflate your tire to bring its level to the one on the other side. 

Reason 4: The Deck Is Unbalanced

For your zero-turn mower to cut the grass evenly, both sides of the deck must be on the same level. If they’re not, they’re the reason your mower is leaving a strip of grass behind.

To find out if that’s your problem, park your zero-turn on level ground. 

Then measure the distance from the blade to the ground on both sides. If one measurement turns out more than the other, your deck is unbalanced.

More often than not, the user manual will tell you how to proceed in this case. So, it’d be wise to grab it and look for some kind of solution for an uneven deck.

Reason 5: The Spindle Is In Bad Shape

When the spindle is in bad shape, it directly affects your blade’s performance. For example, it’ll cause the blade to vibrate when cutting, which may or may not result in an unevenly cut lawn. 

To make sure that the spindle is alright, you should wear protective gloves and hold the blade from each side. Move it up and down, and check for any sounds. If you hear a knocking sound, the spindle housing likely needs repair. 

The bearings may also need replacements; that’ll most likely be the problem if you’ve owned the zero turn mower for a long time.

Reason 6: The Blade Speed Is Too Slow

For the blades to cut evenly and sharply, their speed must be up to the game. If they’re slacking behind, they may be the reason you’re getting uneven cuts because they’ll miss some of the grass.

When your zero turn mower’s blade tip speed is too slow, you may not be getting the best cut possible. When your mower deck is engaged, make sure the engine is running at full throttle to ensure that your blades rotate at their maximum speeds. Get a little engine repair if your engine no longer has the power it used to have.

Reason 7: Bad Pully Bearing or Deck Belt

The deck belt revolves around your pulleys and turns your mower blades. If you’ve been cutting grass for a long time, the belt may slip and not turn your blades at the high revolutions required for an excellent and even cut. 

Replace the deck belt if it has a glazed, glossy appearance or is deeply embedded in the pulley grooves. A stretched, cracked, or shredded belt is yet another sign that your deck belt needs to be changed.

You must also check the pulleys to verify that they are in good working order and capable of turning the belts. A bearing can go out on a pulley. The pulley won’t sit flat and parallel to the deck as it should. It may also limit your pulley’s rotation, preventing it from turning smoothly.

Using your hand, check each pulley for wear and tear. Feel for a blockage and listen for a sound coming from your bearing. 

Check to make sure the pulley is firmly attached to the deck and isn’t wobbly. If any of these indications are present when checking the pulley, it must be replaced.

Reason 8: The Mower Deck is Plugged In

It’s common for your zero turn mower deck to accumulate grass clippings, mud, and other debris. When the amount of waste reaches critical levels, it can obstruct airflow and the suction created under the deck to lift and cut your grass for a smooth cut.

To keep your mower deck clean, scrape it frequently. It will improve the appearance of your lawn and might prevent overheating and overworking your engine.

When the engine is required to turn blades into a grass buildup with each rotation of the blade, it must work harder.

Although you can’t entirely prevent gathering grass under your deck, a deck spray can help. This isn’t some type of magic potion. It won’t stop all grass from accumulating beneath the deck, but it should decrease how often you scrape it.

It also makes it easier to avoid mowing in rainy weather. Wet grass clumps and obstructs your deck faster than dry grass clippings do. In addition, mowing in wet conditions creates deeper tread marks in the yard, giving it the appearance of a poor cut.

Reason 9: Your Driving The Zero Turn Too Fast for The Conditions

Running your zero-turn over your grass too rapidly will not allow the mower to stand up the grass and cut it evenly. It might cause your mower to push grass aside, resulting in an uneven trim.

Adjust your mowing speed to the conditions you’re dealing with. Thick, tall, hefty grass, for example, necessitates a slower pace than a typical lawn or dry grass. When mowing slopes, you’ll need to reduce your speed.


There are several reasons a zero-turn mower will leave a strip of grass, so start with the most common and easy-to-fix reasons first. Be sure you have a sharpened mower blade. Your deck is level side-to-side and front-to-back. 

Also, check for a plugged deck and make sure you aren’t running your mower too fast for conditions. Finally, if you still can’t figure out why your mower is leaving a strip of grass, take it to a small engine mechanic for further diagnosis.

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