What Makes the PTO on a Lawnmower Burn Up?

Non-Riding Mowers

• On non-riding lawnmowers, the PTO exists solely to drive the grass cutting blade on the underside of the mower. The blade is connected directly to the engine. A burned up PTO on a non-riding mower may be due to debris, such as vines or rope, becoming lodged around the shaft and mower blade. A sufficient buildup of debris can cause enough friction to impede the rotation of the mower blade. Turn off the lawnmower and allow it to cool down before cleaning the underside and the area around the blade connection.

Riding Mowers: PTO Clutch

• Some riding mowers are equipped with a separate clutch for the PTO. This enables the mower operator to depress the separate drive clutch to change gears without a loss in power from the blade or PTO attachment. A faulty PTO clutch can release too early or too late when the pedal is depressed and released, which can potentially lead to damage of the PTO itself. A new PTO clutch will need to be installed.

Riding Mowers: Brake Arm Rollers

• The brake arm rollers press into the clutch plate when the PTO clutch pedal is depressed. Over time, these rollers can wear away. Eventually, the worn rollers begin to chip away at the clutch plate, and the clutch and PTO lock up. A worn clutch plate can smell like a burning brake pad. This situation requires removal of the clutch plate and PTO assembly, as well as the brake arm assembly, in order to repair. It is not a user-serviceable part and will require an authorized technician to fix.

Riding Mowers: PTO Belt

• Ground obstructions can place added friction on the PTO shaft of a riding mower. The PTO shaft is typically turned by a belt attached to the PTO clutch. The added friction of obstructions on the shaft can lead to a slipping PTO belt, which can cause a burning odor. The PTO shaft will need to be cleared of debris, and the belt will likely have to be replaced.