An uneven or stepped cut on a Scag mower comes down to the blade and the deck geometry: a dull or bent blade, an unlevel deck, or uneven tire pressure will all leave ridges, streaks, or scalped patches.
Disconnect the spark plug boot (or remove the key on riders) before checking the blade or deck.
Get your exact fix
Enter your model for an instant diagnosis tuned to your exact Scag — ranked causes, the right parts, and a step-by-step repair guide. Scag commercial zero-turns run Kawasaki, Kohler or Briggs Vanguard power.
Most likely causes
01Dull or bent blade
35%A dull edge tears the grass; a bent blade cuts at different heights across the deck.
How to check: Disconnect the plug and inspect the blade — a dull edge streaks, a bent blade cuts two heights. Rotate the blade and measure each tip from the ground to spot a bend.
Reference: Mower deck & blade service manual
02Unlevel deck
30%A deck that's tilted side-to-side or front-to-back leaves a stepped or ridged cut.
How to check: On flat ground, measure blade-tip height left vs right and front vs rear — more than about 1/8–1/4 inch difference means the deck is out of level.
Reference: Mower deck & blade service manual
03Uneven tire pressure
20%A low tire drops one side of the deck and scalps that side of the lawn.
How to check: Check all tires with a gauge — a low tire drops that side and scalps it. Set them equal to spec and re-check the cut.
Reference: Mower deck & blade service manual
04Worn spindle or bearing
15%A worn blade spindle lets the blade wobble, streaking the cut.
How to check: Engine off, grab the blade and rock it up and down — noticeable play or a rough/growly spin means a worn spindle bearing letting the blade wobble.
Reference: Mower deck & blade service manual
Parts you may need
Tap any part to shop for it on Amazon — prices shown are typical ranges.
- Shop
mower blade
Maybe needed · $12–$30
- Shop
blade spindle assembly
Maybe needed · $20–$45
- Shop
tire pressure gauge
Maybe needed · $6–$12
Links open Amazon in a new tab; as an Amazon Associate we may earn from qualifying purchases.
How to fix it
- 1
Check tire pressure and the blade edge
10 minSet all tires to the same spec pressure — an easy, free fix that levels the deck instantly. Then disconnect the plug and inspect the blade for dullness or a bend. These two checks explain most uneven-cut complaints before you touch the deck adjusters.
The rest of the repair
- 02Equalize tire pressure to spec
- 03Sharpen or replace the blade
- 04Measure blade-tip height side-to-side and front-to-back
- 05Adjust the deck level to spec
- 06Check the blade spindle for play
- 07Test-cut and confirm an even finish
The full guide adds the deck-leveling measurements, blade-tip height targets, and spindle-play check. Run the free diagnosis above to unlock it for your model.
Frequently asked
Why does my Scag mower cut unevenly?
Most often a dull or bent blade, an unlevel deck, or uneven tire pressure. Start by matching tire pressures and checking the blade — then level the deck if the step remains.
How do I level the deck on a Scag mower?
Measure the blade-tip height on both sides and front-to-back on a flat surface, then adjust the deck hangers until the tips match the spec. The full measurements are in the repair guide.
More Scag mower problems