Symptoms
- Grass tips look torn, ragged, or brown a day or two after mowing
- Lawn looks whitish or brownish overall after cutting
- Blade has visible nicks or a rounded edge
- Mower has cut the same blade for a full season or more
Likely causes
- CommonDull blade edgeBlades lose their sharp edge after regular use, especially cutting through debris or sandy soil.
- CommonNicked or chipped bladeHitting rocks, sticks, or roots chips the cutting edge and tears grass instead of slicing it.
- PossibleBent bladeA bent blade changes its cutting angle, making the cut inconsistent as well as dull-looking.
- Less commonWrong blade installed for the mowerAn incorrect replacement blade may not cut properly for the deck design.
What to do
- Disconnect the spark plug wire before doing any work near the blade.
- Tip the mower (carburetor/air filter side up, per the manual) and remove the blade using a wrench or blade removal tool.
- Inspect the edge for nicks, dullness, or bending; a bent blade should always be replaced, not straightened.
- Sharpen the blade with a file or bench grinder to a consistent angle, or install a new blade if it's heavily worn.
- Check the blade is properly balanced after sharpening so it doesn't vibrate excessively when reinstalled.
- Reinstall the blade with the cutting edges facing the correct direction and torque the bolt to the manufacturer's spec.
Tools and parts
- Wrench or blade removal tool
- File or bench grinder
- Blade balancer (optional)
Replacement mower bladeSearch: “lawn mower replacement blade”
When to call a pro
Many hardware stores and small engine shops offer inexpensive blade sharpening if you don't want to do it yourself.
Safety
Use caution
Wear gloves when handling the blade and always disconnect the spark plug wire first.