Riding Mower and Tractor: 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.
These repairs may help solve your Riding Mower and Tractor problem:
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. Examine the blade belt regularly and replace it if it’s worn or broken.
Replace the riding mower mandrel assembly
If a noise comes from the mower deck while the riding mower or lawn tractor is running, or if the mower isn't cutting evenly, you might need to replace the riding mower's mandrel assembly.
Replace the riding mower PTO lever
If the lawn tractor mowing deck won't engage or the lever is broken off, you might need to replace the PTO lever.
Replace the riding mower deck idler pulley
You might need to replace riding mower deck idler pulley if a noise comes from the mower deck when the riding mower or tractor is running, if the belt is loose, or the belt comes off.
Replace the 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.