why does my riding lawn mower cut unevenly

by Mervin Blanda Published 3 years ago Updated 2 years ago

Most Common Causes of a Lawn Mower Cutting Uneven

Wheels are Set to Different Heights. On some lawn mowers, the height of each wheel must be set individually. ...
One or More Wheels is Damaged. ...
Cutting Blade is Loose. ...
Mower Blade is Dull. ...
Mower Blade is Bent. ...
Crankshaft is Bent. ...
Cutting Deck is Clogged. ...
The Deck is Damaged. ...

A riding mower can begin cutting uneven when a tire pressure is low; a blade is bent or installed incorrectly; the deck is not level; a bearing is bad in the spindle housings or pulleys; the blades or belt is worn; the engine speed is too low; or there is operator error.

Full Answer

Why does my John Deere lawn mower give me an uneven cut?

A John Deere lawn mower may give you an uneven cut when the tire pressures are not correct, the mower blades are worn or damaged, the spindle bearings are damaged, the deck is not level, the mower deck is clogged or the ground speed is too fast.

What causes uneven lines on a lawn mower blade?

In lawnmowers, the part that houses the blade is the deck. A tilted or loose deck could cause uneven lines when mowing. The deck may break down with age or bend due to normal wear, and tilting is sometimes a manufacturing mishap. The blade and deck in some mowers are connected, and a tilted deck could cause an uneven cut.

Why does my lawn mower keep cutting step?

Step cutting is usually caused by mower deck damage, misadjustment, or mower blade damage. Normally the deck just needs to be re-leveled. To check for this:

How do you fix a lawn mower that keeps cutting unevenly?

Adjust all four wheels to the same height setting. If the grass is long, then use the high setting to avoid overworking the lawnmower and producing an uneven cut. If the wheels are properly adjusted and the mower still cuts unevenly, it's time to check the cutting blade.

What causes a riding mower to cut uneven?

Some of the most common causes of a lawn mower cutting unevenly include damaged wheels, a loose, bent or dull mower blade, a bent crankshaft, and a clogged or damaged cutting deck.

How do I get my riding mower to cut even?

1:302:45Leveling a Riding Lawn Mower Deck for an Even Cut - YouTubeYouTubeStart of suggested clipEnd of suggested clipHold the adjustment nut with one and tighten the jam nut with a second wrench. That's. It you justMoreHold the adjustment nut with one and tighten the jam nut with a second wrench. That's. It you just leveled your mower deck side to side and front to back.

Why is my John Deere riding mower cutting uneven?

Why is my lawn mower not cutting well?

0:102:10Why is My Lawnmower Cutting Poorly or Unevenly? - YouTubeYouTubeStart of suggested clipEnd of suggested clipIf your wheel adjusters aren't all set to the same level you won't have a consistent mowing heightMoreIf your wheel adjusters aren't all set to the same level you won't have a consistent mowing height check. And adjust them accordingly and inspect for any damage or wear replacing.

Why is my mower leaving a strip of grass?

Lawnmowers are designed to run at full throttle when their mowing blades are engaged. Anything less than full throttle results in poor cutting, which includes those annoying streaks of grass left behind with each pass. Ensure you cut grass with your lawnmower running at full throttle.

Should a mower deck be higher in the front or back?

For most effective results, a lawn mower deck should have a pitch, or height difference of 1/8-inch to 1/2-inch between the front of the deck to the back of the deck. Naturally, this makes the sweet spot about 1/4-inch of pitch, depending on the mower model.

Should a mower deck be level front to back?

For most effective results, a lawn mower deck should have a pitch of 1/8-inch to 1/2-inch between the height of the deck rear to the height of the deck front. Naturally, this makes the sweet spot about 1/4-inch of pitch, depending on the type of mower.

Should mower deck wheels touch the ground?

Mower deck gauge wheels should be properly adjusted to prevent scalping grass on uneven terrain. The bottom of the wheels should sit approximately 1/8-1/2 of an inch from the ground, depending on your cutting height.

How do I know if my lawn mower blade is balanced?

0:332:09How to Balance Mower Blades : Lawnmower Maintenance & RepairYouTubeStart of suggested clipEnd of suggested clipLet it come to rest and look for which side of the blade sits a little lower than the other the sideMoreLet it come to rest and look for which side of the blade sits a little lower than the other the side that sits lower is the side with more metal and you'll need to grind a little more off that.

How can I make my lawn mower cut better?

2:3313:29HOW TO MAKE YOUR OLD LAWN MOWER CUT BETTER THAN NEWYouTubeStart of suggested clipEnd of suggested clipPer the rotation of your lawnmower. Now you want to sharpen it all the way from here all the way toMorePer the rotation of your lawnmower. Now you want to sharpen it all the way from here all the way to the end that way you know as you're going through cutting.

Why is my Cub Cadet mowing uneven?

A Cub Cadet mower can cut uneven when the mower deck is plugged, not level, or the shell is damaged. Damaged spindles, bad bearings, bad pulleys, dull blades and worn deck belts can affect your cut. There are many things that can affect your cut and leave you with a bad looking yard.

How do you balance lawn mower blades?

0:332:09How to Balance Mower Blades : Lawnmower Maintenance & RepairYouTubeStart of suggested clipEnd of suggested clipThe easiest way I think to do it is to just clamp a nail into a vise. Then you can set the blade onMoreThe easiest way I think to do it is to just clamp a nail into a vise. Then you can set the blade on the nail through the blade Center hole.

How do you fix a uneven lawn mower blade?

3:538:575 REASONS WHY YOU'RE MOWING UNEVENLY & HOW TO FIX IT ‍YouTubeStart of suggested clipEnd of suggested clipOn the tractor portion those brackets that hang down you're going to have threaded brackets of some.MoreOn the tractor portion those brackets that hang down you're going to have threaded brackets of some. Kind. Sometimes you'll be able to to loosen them and adjust with a wrench.

How do you level the blades on a riding lawn mower?

4:095:45How to Adjust and Level the Deck Height of a Riding Lawn Mower ...YouTubeStart of suggested clipEnd of suggested clipThe blade to a point that the difference between the front tip to the rear tip is 1/8 to one half ofMoreThe blade to a point that the difference between the front tip to the rear tip is 1/8 to one half of an inch. Lower. To make the adjustment use the appropriate size wrench to loosen the jam nut

Why is my lawn mower not cutting evenly?

If a lawnmower does not cut evenly, the most probable cause is mower deck damage and misadjustment, resulting in an uneven cut. To fix the problem, several things need to be checked: The Tire Pressure.

Why is my lawn mower's desk height misadjusted?

While riding a mower, sometimes, it hits the bumps and debris that make the desk height misadjusted. However, sometimes while changing blades, the desk level is also disturbed. If the desk is not leveled, then you may face this issue. Leveling the deck under the mower is very important to cut the grass more precisely.

How to level a lawn mower?

To balance the desk, first park it on a flat surface. Stabilize the mower and ensure the blades and moving parts have stopped. After that, check the tires’ pressure and then measure the height of blades from the edge to the ground. If the difference between the peaks is more remarkable, then adjust it by lifting the link lock. Turn in clockwise to raise the mower and in an anti-clockwise direction to lower it. Adjust until the blade height difference is within 1/8 inches. Use a measuring tape to measure the heights. If the front blade tips are 1/8 inch to ½ inch lower than the rear blade tips, this is acceptable.

Why level the deck under a lawn mower?

Leveling the deck under the mower is very important to cut the grass more precisely. It would help if you dropped the mower deck to avoid uneven cutting. You should check the heights of the desk before and after changing the blades to remain adjusted.

What happens if my lawn mower deck is not leveled?

1.2 ● Step 2. If the mower deck is not leveled, then it will cut uneven grass.

How to adjust mower blades?

Turn in clockwise to raise the mower and in an anti-clockwise direction to lower it. Adjust until the blade height difference is within 1/8 inches. Use a measuring tape to measure the heights. If the front blade tips are 1/8 inch to ½ inch lower than the rear blade tips, this is acceptable. 3.

What causes deck pulleys to vibrate?

Worn deck pulleys cause the blades to vibrate.

Why is my riding mower cutting unevenly?

A riding mower can begin cutting uneven when a tire pressure is low ; a blade is bent or installed incorrectly; the deck is not level; a bearing is bad in the spindle housings or pulleys; the blades or belt is worn; the engine speed is too low; or there is operator error.

Why is my riding mower blade bent?

A bent mower blade on your riding mower can cause your mower to give you a bad or uneven cut. When the blade impacts a solid object, like a tree root, rock, or toy, it can bend the blade. Take time to walk your yard prior to mowing to minimize the potential of bending your mower blade.

What does it mean when a mower blade is not balanced?

A balanced mower blade is one where the weight is equal on each side of your blade. When it is not balanced, you will have movement when the blades are engaged. This can also cause spindle bearing damage and additional movement in the blade contributing to your uneven cut.

What does the bottom of a lawn mower blade mean?

Some mower blades have a marking on them indicating the way a blade is to be installed. You may see “BOTTOM” or “THIS SIDE DOWN” stamped into the blade to assist you with installation. If you don’t have writing on your blade, don’t worry. Just remember “Sail Up!” and you’ll install your blades correctly.

Why is my lawn mower blade dull?

Dirt that is swirling in your mower deck can cause your mower blades to become worn and dull. The mower blade and deck are designed to create air movement and a suction under the deck to lift grass tall for a precise cut. Not only does it lift grass, it also draws dirt under the deck.

What causes a mower deck to not sit level?

Before continuing any further, you must check your tire pressures. Something as simple as a low tire can cause your mower deck to not sit level causing an uneven cut. Make sure the pressures are as shown on the tire side wall.

What happens if your deck doesn't sit level?

A deck that doesn’t sit level will give you an uneven cut. Measure your deck from side-to-side to check for equal measurements. The leveling procedures vary from one riding mower to another so it is best to refer to your owner’s manual for the correct procedures for your mower.

What causes a riding lawnmower to cut uneven – Frequent reasons

Let’s go through the common reasons. A simple problem such as a flat tire can affect the lawnmower’s performance. Check the below parts first if the lawnmower is cut unevenly:

Why does the lawnmower cut uneven – Riding technique issues

Although there is nothing wrong with the mower deck, the lawnmower can cut unevenly because of the incorrect operation. Please check the list. Then make sure that you don’t make a mistake.

Why does the lawnmower cut uneven – The failure of the cutting parts

There is the fact that the lawn can’t work perfectly if they are dull blades. You can approach some responsibility of the blade in reducing the performance.

What causes a riding lawnmower to cut uneven – Other reasons

The spindle helps connect the housing with the bearing. If it is bent or loose, your lawnmower will cut unevenly.

Final thoughts

It can take you one to several hours to solve the problem. However, the result is rewarding. You will not be annoyed by the bad cutting lines.

Why is my riding lawn mower cutting unevenly?

The most common cause of uneven cuts in riding lawnmowers is incorrect weight distribution. If the weight distribution is unchecked, then your mower is likely to mow unevenly.

Why does my lawn mower cut uneven lines?

A mower cuts uneven lines because the deck, wheels, or blades aren’t leveled. You can use a measuring tape to check the distance between the deck and ground to be sure. Wet grass, loose parts, and uneven weight distribution also cause choppy cuts in the lawn.

Why is my lawn choppy?

Inadequate mowing speed will leave your lawn with choppy lines. Operating the mower at a slower frequency over the yard will leave uneven stripes. The blades spin slow and give your yard an imperfect cut if the engine speed is low. On the other hand, moving too quickly could lead to imprecise cuts.

How to check for uneven lines on lawn mower?

Check the distance between the blade tips to the level surface using a tape measure. A height difference between the blades shows misalignment, and this is causing the uneven lines. Keep your mower blades sharp as blunt or worn out blades may cause the mowing to be rugged.

Why is my riding mower tilting?

In riding mowers, uneven mowing is due to uneven pressure in the wheels, making the mower tilt to its side. According to Jack’s Small Engines, if you notice a slanted stair steps kind of appearance on the cut grass, you need to inflate your mower tires according to the recommended specification.

What causes uneven lines on lawn mower blades?

How to check if a lawn mower is flat?

To check if this is the case, park your mower on a flat level surface such as a driveway, then use a tape measure to compare the height deck from the level surface on both the left and right sides. The two measurements should be the same.

John Deere Mower Blade is Worn or Dull

A John Deere blade that is very worn can leave behind strips of uncut grass between the blades. This occurs when dirt is sucked into your mower deck and wears down the metal of your blade. There is no way to prevent wearing of your blade. It’s just a common wear item on your mower.

John Deere Tire Pressures are Not Correct

When you notice your John Deere is cutting the lawn unevenly, you may immediately start looking at your mower deck to resolve the problem. While there are many items on the deck that can cause this problem, you must first check your tire pressures.

John Deere Mower Blade is Bent

A bent mower blade, whether it’s slightly bent or severely bent, can cause your John Deere to give you a bad and uneven cut. You can bend a blade when it contacts a solid object. This could be a tree root, rock, dog toy or some other object left in your yard.

John Deere Mower Blades are Installed Incorrectly

I’ve had customers call telling me their new mower is cutting terribly. On many occasions, I have found the first time they installed their blades they installed them incorrectly. The blades were put on upside down. Of course, placing blades upside down will cause an uneven cut.

John Deere Mower Deck is Plugged with Grass

A mower deck that is clogged with grass and dirt can cause a bad and uneven cut. Your John Deere mower deck is designed to use the air flow created by your mower blades and area under your deck to create a suction. This suction makes your grass stand tall while your mower blade passes by and cuts the blades of grass.

John Deere Mower Deck is Not Level

A John Deere with an unlevel deck will give you an uneven cut. The deck leveling procedures vary among the different John Deere models. Refer to your owner’s manual for instructions and specifications to adjust your mower deck. Follow the your owner’s manual to level the deck from side-to-side and front-to back.

John Deere Spindle is Bent or Spindle Bearing is Bad

A bent spindle or bad bearing in the spindle housing can cause your mower blades not to give you a good cut because your blade may sit unlevel. Identify if you have a problem in your spindle housing by first putting on a good pair of gloves to protect your hands from the sharp edges of your blades.

What causes a mower deck to cut off?

Step Cutting. Step cutting is sharp ridges left in the lawn surface. Step cutting is usually caused by mower deck damage, misadjustment, or mower blade damage.

Why is mowing so tough?

The topology of the ground can make mowing tough.

Why does my lawn mower stutter?

Streaking is when thin strips of uncut grass are left behind the mower. Streaking is usually caused by operator error or poor blade maintenance. Streaking can occur if the engine speed is too low. All mowers are designed to run at full throttle. Believe it or not you are doing more harm to your engine by running it slower than full throttle when you are mowing. Blades need to be spinning at the correct blade tip speed. They need to be sharp and not have too much wear on the uplifts. The speed and uplifts pull the grass up just like the barber lifts your hair up with a comb to get a straight cut. The air movement within the cutting deck is very important. Decks plugged with grass clippings can not move the air the way they were designed to do.

How to turn a tractor blade perpendicular?

Manually turn the blades perpendicular with the direction the tractor is sitting. Measure the outer tip of the left blade to the surface your parked on (don't measure from the deck shell, it has to be from the blade tip). Write the measurement down.

What to do if your deck blades are not the same?

The two measurements should be the same. If the measurements are a 1/4" or more off, it needs to be corrected. The next thing to do is to turn the blades and measure again. If the measurements are not the same, one of the blades is probably bent. Other things to check for are damage to the deck shell, and bent or loose spindles.

Why does my tractor have streaking?

If the operator does not over lap the cutting row enough or makes very tight turns, marks can be left in the lawn. The easy way to see the cause of this is to use a jack to raise one rear wheel of the tractor a little off the ground. If your tractor does not have a full free floating deck doing this will cause the deck to tilt. This tilting in tight turns and when one wheel is lifted higher than the other by uneven ground contours will leave marks. The only fix for this is to slow down, make wide turns, over-lap cuts, or buy another tractor with a free floating deck.

Why are my tires not cutting cleanly?

In this case your tires could be low or the ground soft from rain to your riding lower. Your blade could be dull here as well so it isn't cutting cleanly (other than hitting the ground).

What affects the performance of a Craftsman mower?

A number of factors can affect engine performance, including fuel quality, condition of the spark plug and dirt in the fuel lines or carburetor. Craftsman lawnmowers have a speed control located near the priming bulb, and that control should be set to the "Fast" position while the mower runs.

How to remove blade from lawn mower?

The blade can be removed from the mower while the mower is on its side. Stabilize the blade with a block of wood to prevent it from turning, and then loosen the blade bolt with a 9/16-inch wrench. Sharpening the blade yourself requires putting it in a vise and grinding its cutting edge with a grinder.

How to adjust height on Craftsman lawn mower?

A height adjustment lever is behind each wheel and protrudes above the wheel's top. Adjust a wheel's height by squeezing the lever against the wheel while you move the wheel to put the lever in a different setting. The wheels have only three height settings -- low, medium and high. Adjust all four wheels to the same height setting. If the grass is long, then use the high setting to avoid overworking the lawnmower and producing an uneven cut.

How many height settings does a lawn mower have?

The wheels have only three height settings -- low, medium and high. Adjust all four wheels to the same height setting. If the grass is long, then use the high setting to avoid overworking the lawnmower and producing an uneven cut.

Do Craftsman mowers have sharp blades?

Whether you use your Craftsman lawnmower to mulch grass clippings, to collect them in a grass catcher or to discharge them through a side shoot, the mower needs a sharp cutting blade to produce an evenly cut lawn. If you're sure the blade is sharp, however, and your lawn still has streaks or patches of unevenly cut grass, ...