Riding Mowers & Tractors: Why is my riding mower not cutting evenly?
If your riding lawn mower is cutting the grass unevenly, start by checking the pattern of the cut. If the cut looks like slanted stair steps, inflate the tires to the manufacturer's recommendation and level the mower deck. If you see alternating stripes of taller and shorter turf, slow down while mowing--mowing too fast can cause those stripes. If slowing down doesn't fix the stripes, sharpen or replace the mower blades. Sharpening or replacing the mower blades is also the answer if grass tips look ragged or tattered instead of cleanly cut.
Blade vibration also causes an uneven cut. To eliminate vibration, replace unbalanced blades and worn mandrels. Replace a worn blade belt because a worn belt won't spin the blades correctly. Worn deck idler pulleys can also cause vibration, so replace any deck pulleys that don't spin freely. Check the mower deck for damage and replace the deck if it's bent. Finally, tune up the mower engine if it doesn't run smoothly when mowing.
THESE REPAIRS MAY HELP SOLVE YOUR RIDING MOWERS & TRACTORS PROBLEM
Replace the riding mower mandrel assembly
The mandrel assembly attaches to the deck and spins the blade to cut grass. A blade won't move if the mandrel locks up. A damaged mandrel causes mower deck vibration and uneven cutting. Examine the mandrels regularly and replace any damaged mandrels.
Riding mower mandrel assembly
How to replace a mandrel assembly on a riding lawn mower
If the blade shaft on your riding lawn mower vibrates or won't spin the blade, the mandrel might be worn or damaged. This DIY repair guide and vidoe explain how to replace a riding lawn mower mandrel assembly in just 6 steps.
Level the mower deck on a riding mower
A tilted mower deck can cause uneven cuts. Park the lawn tractor on a flat surface and inflate all 4 tires evenly. Lower the deck to the cutting position and position the blades sideways. Measure the height of the cutting blade outer edges. Adjust the mower deck hangers to level the mower blades for an even cut. Watch our How to level a riding lawn mower deck for an even cut video for detailed mower deck leveling instructions.
Level the mower deck on a riding mower
Replace a riding mower blade
A bent mower blade won't cut grass evenly and may cause mower deck vibration. Dull blades leave ragged edges on cut grass. Inspect mower blades regularly and replace a riding mower blade if it's damaged, bent or dull.
Replace a riding mower blade
How to replace a riding lawn mower blade
If brown, tattered grass tips make your lawn look sick, one or more blades on your riding mower could be dull or bent. This repair guide and video show how to replace a riding mower blade in 30 minutes or less.
How to replace a cutting blade on a zero-turn riding mower
If your grass looks tattered after mowing with a zero-turn riding, the problem could be a dull or damaged blade. This easy-to-follow repair guide and video explain how to replace a blade on a zero-turn riding lawn mower.
Replace the riding mower blade belt
The blade belt spins the blades to cut the grass. A worn or broken drive belt won't spin the cutting blades so your mower won't cut the grass. A worn blade belt can also cause mower deck vibration or uneven cuts. Examine the blade belt regularly and replace it if it's worn or broken.
Riding mower blade belt
How to replace the blade belt on a zero-turn riding mower
If the blades won't spin on a zero-turn riding mower, the problem could be a broken blade belt. Replace a broken or worn blade belt on a zero-turn riding lawn mower by following the steps in this DIY repair guide and video.
How to replace a riding lawn mower blade drive belt
If the blades on your riding lawn mower don’t spin fast enough—or don’t spin at all—the blade drive belt could be worn out or broken. This repair guide and video show how to replace a blade drive belt in less than an hour.
Tune up the riding mower engine
The engine tune-up includes routine maintenance for a riding lawn mower or tractor. Engine performance suffers if you don't regularly tune up the engine. A poor-running engine may stall when you try to drive the mower. You may notice uneven cuts if the engine doesn't run smoothly when you're mowing grass. Routinely tune up the engine by replacing the engine oil, oil filter, air filter, fuel filter and spark plug. The tune-up also includes checking the ignition, carburetor, battery, throttle and choke controls, as well as cleaning the engine cooling fins.
Tune up the riding mower engine
How to replace a riding lawn mower fuel filter
If your riding lawn mower’s engine runs rough or won't run, the fuel filter could be dirty. This repair guide and video show how to easily replace the fuel filter on your riding lawn mower in 15 minutes.
How to replace a riding lawn mower spark plug
If your riding lawn mower engine runs rough or is hard to start, it might be because the spark plug is damaged. This DIY repair guide and video show how to replace the spark plug on a riding mower in 15 minutes or less.
How to replace the air filter on a riding lawn mower
If your riding lawn mower runs rough or stalls after starting, the air filter could be dirty. This DIY repair guide and video show how to replace a clogged riding mower air filter in less than 15 minutes.
Replace the mower deck on a riding mower
The mower deck houses the cutting blades, mandrel pulleys and blade drive belts. You may see uneven cutting if the mower deck gets damaged because the deck. Severe rust can corrode the deck, causing holes in the deck. Replace the mower deck if it's damaged or there's a lot of rust.
Mower deck on a riding mower
How to remove the mower deck on a zero-turn riding mower
Need to remove the mower deck on a zero-turn riding lawn mower but aren't sure how? This DIY repair guide and video show how to remove the mower deck in 6 easy-to-follow steps.
Replace the riding mower deck idler pulley
The deck idler pulley tightens the blade belt against the blade pulleys to spin the blades when you shift the blade engagement lever to engage the blades. You might need to replace the riding mower deck idler pulley if the blades don't spin. A worn idler pulley can also cause uneven cuts and mower deck vibration, so check the idler pulley if you notice these symptoms. Replace the deck idler pulley if it's worn or broken.
Riding mower deck idler pulley
Most common symptoms to help you fix your riding mowers & tractors
Choose a symptom to see related riding mower and lawn tractor repairs.
Main causes: faulty battery, bad alternator…
Main causes: damaged cutting blade, worn deck pulley, damaged mandrel pulley, loose fasteners on mower deck components…
Main causes: damaged tie rods, bent or worn wheel spindle, worn front axle, damaged sector gear assembly…
Main causes: worn or broken blade belt, broken belt idler pulley, blade clutch cable failure, bad PTO switch, damaged ma…
Main causes: punctured tire or inner tube, leaky valve stem, damaged wheel rim…
Main causes: engine overfilled with oil, leaky head gasket or sump gasket, damaged carburetor seals, cracked fuel pump, …
Main causes: clogged carburetor, damaged flywheel key, dirty spark plug, stale fuel, improper valve lash, engine needs a…
Main causes: shift lever needs adjustment, neutral control needs adjustment…
Main causes: worn or broken ground drive belt, bad seat switch, transaxle freewheel control engaged, transaxle failure, …
Most common repair guides to help fix your riding mowers & tractors
These step-by-step repair guides will help you safely fix what’s broken on your riding mower or lawn tractor.
How to replace the starter motor on a riding lawn mower
If you hear the solenoid click but don’t hear the starter motor spin when you turn the key, follow these steps to replac…
How to rebuild a riding lawn mower carburetor
Get your sputtering carburetor running smoothly in 60 minutes.…
How to replace a riding lawn mower rear tire
Your mower can’t run on a damaged rear tire. Here’s how to install a new one.…
Effective articles & videos to help repair your riding mowers & tractors
Use the advice and tips in these articles and videos to get the most out of your riding mower or lawn tractor.
Learn about all the convenient features on our Sears PartsDirect website that make your parts purchases easier.…
Get answers to frequently asked questions about Sears and Sears PartsDirect.…
Check the starter solenoid, starter motor, wiring, battery and engine.…