Riding Mowers & Tractors: Won't cut grass
If the riding lawn mower runs but the blades won't cut the grass, the problem could be with the blade belt. Examine and replace the belt if you find it worn or broken. If the belt is okay, check the blade belt idler pulley, blade clutch cable and clutch lever assembly on tractors with manual blade actuators. On riding mowers that use a PTO switch to activate the blades, check the PTO switch and the electric clutch. Failed mandrel pulleys can also prevent the blades from spinning properly.
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.
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.
Replace the riding mower blade engagement lever
The blade engagement lever pulls the blade clutch cable to spin the blades when you shift the lever to the engaged position. The blades won't spin-read: cut grass-if if the lever breaks. If the blades don't spin, examine the lever and replace it if it's broken.
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.
Replace the riding mower blade clutch cable
The blade clutch cable tightens the blade belt to spin the cutting blades when you shift the blade clutch lever to the engaged position. Blades won't spin when you push the engagement lever if the blade clutch cable is worn or broken. Examine the cable when the blades won't turn. Replace the blade clutch cable if you find it worn or broken.
Replace the riding mower electric clutch
The electric clutch mounts to the engine crankshaft and controls the mower's cutting blades. The blades won't spin if the electric clutch is defective. Replace the electric clutch if it won't engage the blades when activated.
These step-by-step repair guides will help you safely fix what’s broken on your riding mower or lawn tractor.
Replace the mandrel assembly if the blade shaft vibrates or doesn't spin.
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