Why is my mower leaving an uneven cut?
Usually dull, bent or unbalanced blades, a deck that is out of level, uneven tire pressure, or clippings packed under the deck. Check tire pressures, scrape the deck, inspect the blades, then measure from the floor to each blade tip: Ariens says the sides should match within 1/8 inch. Wet or tall grass and driving too fast also cause it.
Free to ask. Local shops send quotes, and you pay only when you book one.
By Kasra Taheri, Founder, LoclisPublished
Researched and drafted with AI, then checked claim by claim against the sources listed below before it was published. Prices and rules change; the dates beside each source say when it was last checked.
Step by step
Read when to stop and call a pro, further down this page, before you start.
Step 1: Disable the mower
Park on level ground with the engine off, then disconnect the spark plug wire or remove the battery before your hand goes near the blades.[1]
Step 2: Set the tire pressures
Inflate every tire to the pressure in your manual, because under or over inflated tires prevent a correct deck adjustment.[2]
Step 3: Clean the underside of the deck
Scrape off caked clippings with a putty knife and let the deck dry.
Step 4: Inspect each blade
Look for bends, cracks, nicks and a dull edge, and replace a blade that is bent or cracked.[2]
Step 5: Check blade balance
Slide the blade onto a steel bolt or pin held level and see whether either end drops.[3]
Step 6: Measure the deck side to side
Measure from the floor to the blade tip on each side, rotate the blade 180 degrees and measure again.[3]
Step 7: Adjust if the sides differ
If the difference is more than 1/8 inch (3 mm), adjust the deck links as your manual describes.[3]
Step 8: Test mow
Mow dry grass, removing no more than a third of its length, at a slower speed.[3]
Start with the cheap causes
An uneven cut usually comes from one of five things: dull or bent blades, an unbalanced blade, a deck that is not level, tires with different pressures, or clippings packed under the deck. Work through them in that order, because the first and last cost nothing to check.
Husqvarna's troubleshooting chart for "Uneven mowing results" lists "Unequal air pressures in tires", bent blades, an uneven mower deck suspension, dull blades, driving speed too high, grass that is too long and grass collected under the mower deck.[2] Those are the same suspects, so a pattern in the lawn tells you where to look.
Read the pattern in the grass
- Ragged, brown-tipped grass everywhere. That is a dull blade. Dull blades bludgeon, rip, and tear grass blades leaving ragged wounds that are more difficult to heal.[1]
- Stripes or steps, one side cut lower than the other. The deck is out of level, or the tires on one side are low. The Husqvarna manual is blunt about it: "Faulty mower deck adjustments will cause an uneven mowing result."[2]
- Clumps, patches left standing or windrows. Wet or tall grass, packed clippings under the deck, or driving too fast. Ariens: "Wet grass tends to pack inside mower pan and will not disperse evenly."[3]
- Wavy cut with heavy vibration. A bent or unbalanced blade. An unbalanced blade can create a slight wobble that causes strain on a mower and may result in an uneven cut.[1]
If you have a ragged-looking lawn rather than steps and stripes, the blade is the first thing to deal with.
Check the easy things first
Tire pressure is the one people skip. On a riding mower or zero-turn, a soft tire on one side tilts the whole deck, and the manual's pressure is what the deck settings assume. "If tires are under or over inflated, the deck cannot be correctly adjusted."[2] Set every tire to the pressure on the sidewall or in your manual before you touch the deck.
Then look at how you mow. Ariens advises setting the deck height so that no more than 1/3 of the total grass length is removed at any one time,[3] and says "Grass should be cut when it is dry, not when it is wet from dew, rain or from watering."[3] If grass does not disperse evenly, it is possible that too much grass is being removed per cutting, grass is too wet or travel speed is too fast.[3] A slower pass, a higher first cut and a dry lawn fix more uneven cuts than any repair does.
Scrape the deck, then look at the blade
Clippings caked under the deck stop grass from flowing through it. Follow how to clean under a mower deck first. "Whenever your hand goes near the blades always disconnect the spark plug for gas-powered or remove the battery for electric mowers."[1]
With the deck clean, look at each blade. Ariens: "Replace bent, worn or damaged blades."[3] Husqvarna: "Replace blades that have been bent or cracked when hitting obstacles."[2] A blade that has hit a stump or rock often looks nearly straight, so lay it on a flat surface or compare it with a new one.
Balance matters after sharpening. The home test is simple: "To check blade balance, use a steel bolt or pin."[3] Husqvarna: "The sharpening of blades must be carried out by an authorized service workshop."[2] Ariens: "We do not recommend sharpening blades, but if you do, be sure the blade is balanced."[3] See how to sharpen mower blades for the details.
Check the deck level
Park on a flat, level surface with the tires correctly inflated. Turn the blades so the tips point side to side, and measure from the floor to the blade tip on each side, then rotate the blade 180 degrees and measure again. Ariens: "The measurement should be equal within 1/8 inch (3 mm) side to side."[3]
If the sides differ, adjust the deck's height links as your owner's manual describes. On the Ariens EZR the fix is to raise the low side and lower the high side by half the difference each. Husqvarna: "Adjust the deck slightly higher in the rear."[2] The manual for your model gives the exact pitch and adjuster locations, and some decks need the drive belt installed before leveling, so follow it rather than guessing.
Stop and call a pro if
- The deck is bent, cracked or rusted through around the blade housing or spindle mounts.
- A spindle wobbles or the blade will not spin freely. Bearings and spindles are a shop job.
- The deck will not hold its level after you adjust it, which points to worn or bent lift arms and links.
- The vibration continues with a new, balanced blade.
Getting help in Virginia
Once the deck is level and the blades are good, keep it that way by keeping the deck from rusting. Browse more lawn equipment answers, or see lawn equipment repair businesses on Loclis.
If it still cuts badly after these checks, describe the problem and a local mower shop can quote the repair.
Common questions
- Can a dull blade make a mower cut unevenly?
- Yes. A dull blade tears the grass instead of cutting it, leaving ragged, brown-tipped tops. University of Illinois Extension says dull blades bludgeon, rip, and tear grass blades. Sharpen or replace the blade, and balance it after sharpening.
- How do I know if my mower deck is level?
- Park on a flat surface with the tires correctly inflated, then measure from the floor to the blade tip on the left and right of the deck. Ariens says the two measurements should be equal within 1/8 inch (3 mm). Your manual gives the model's exact spec and the adjusters to use.
- Why does my mower leave strips of uncut grass?
- Most often wet or tall grass, clippings packed under the deck, or driving too fast. Ariens says too much grass per cutting, wet grass or fast travel speed can stop the clippings dispersing evenly. Raise the first cut, let the lawn dry, slow down and scrape the deck.
- Do low tires really affect the cut?
- Yes. A soft tire on one side tilts the deck, and Husqvarna's manual says that if tires are under or over inflated, the deck cannot be correctly adjusted. Set the pressures first, then measure the deck.
- Should I sharpen the blade myself?
- Manufacturers differ. Husqvarna says sharpening must be done by an authorized service workshop, and Ariens does not recommend home sharpening but says to keep the blade balanced if you do. A shop sharpening is a safe default.
Sources
- [1] Mower Maintenance, University of Illinois Extension. Checked October 28, 2026.
- [2] Operator Manual MZ 54 (967 696102-00), Husqvarna. Checked October 28, 2026.
- [3] EZR Zero Turn Mower, Owner/Operator Manual, Ariens Company. Checked October 28, 2026.
Want a pro to handle it?
Describe the job once. Licensed local businesses send quotes, and you pay only when you book one.
Get a quote for Lawn Equipment