How to Change the Mower Deck Belt on a Riding Lawn Mower

Over time, the belts on your MTD riding lawn mower can wear. Changing your mower deck belt as necessary will help keep your machine running at its peak.

Before you change your Riding Mower Belts, confirm that the part number for the replacement you purchased matches the one listed in the "replacement parts" section of your MTD lawn mower manual. Always use Genuine Factory Riding Lawn Mower Parts, as they are specifically designed for your machine and will help maximize its performance. Keep in mind that the instructions for changing your mower deck belt may be slightly different for your model.

Step 1: Prevent unintentional starting

Before you change the mower belt, turn off the engine, remove the ignition key and disconnect the spark plug wire(s) to prevent accidental starting while you're working.

Step 2: Adjust the deck height

Adjust the deck on your riding lawn mower to the lowest position by moving the deck lift lever.

Step 3: Take off the mower deck belt guards

Remove the mower deck belt guards by taking out the screws that secure them to the deck.

Step 4: Take off the belt-keep rod

Remove the belt-keeper rod from around the engine pulley.

Step 5: Loosen the idler pulley nuts

On a riding mower deck like the one in the video, loosen - but don't remove - the idler pulley nuts. This will enable you to easily remove the mower deck belt from around the idler pulleys.

Step 6: Snap a photo

If you have a digital camera or a cell phone with a camera, you may want to take a picture of how the mower deck belt is routed before you remove it.

Step 7: Take off the mower deck belt

Remove the mower deck belt from around all the pulleys, including the deck idler pulleys. Don't put your fingers on the idler spring or between the mower deck belt and any of the pulleys, as this could cause your fingers to get pinched or injured.

Step 8: Install the new mower deck belt

Route the new mower deck belt in the same manner as the old one. If you took a photo earlier, use it for visual reference. Or, you can refer to your operator's manual.

Step 9: Secure the idler pulley nuts

Tighten the idler pulley nuts you loosened.

Step 10: Replace the belt-keeper rod

Put the belt keeper rod back in place around the engine pulley.

Step 11: Put the mower deck belt guards back on

Remount the mower deck belt guards.

Step 12: Raise the deck

Raise the deck on your riding lawn mower back to the highest position.

Step 13: Replace the spark plug wires

Reconnect the spark plug wire(s).

Step 14: Warm up your machine

Put the key back in the ignition and start the unit. Let it warm up a little before attempting to engage the mower deck. (If you're working in a garage, make sure the door is open for adequate ventilation).

Step 15: Engage the mower deck

Place the throttle control at full throttle and engage the mower deck.

Step 16: Check for abnormal sounds

Disengage the mower deck, and wait for the mower deck belt to come to a complete stop. Engage the mower deck again. Listen for any abnormal sound.

Step 17: Turn off your machine

Disengage the mower deck, bring the throttle down to idle, and turn off the riding lawn mower.

Step 18: Remove the keys and spark plug wire(s)

Remove the ignition key and the spark plug wire(s). Before checking the mower deck belt, ground the spark plug wire(s) against the engine to prevent unintended starting.

Step 19: Lower the deck

Adjust the deck to the lowest position.

Step 20: Inspect the mower deck belt

Check the mower deck belt to ensure it's properly running through all the pulleys and that no damage is present.

Step 21: Reconnect the spark plug wire(s)

Once you've changed your mower deck belt and checked your work, you can re-install the spark plug wire(s).

Fix equipment issues quickly

When you need parts for your walk-behind lawn mower or riding lawn mower, you can use the MTD Genuine Parts Part Finder to find the correct one. Common parts include:

The MTD Genuine Parts Knowledge Center provides do-it-yourself instructions for performing many basic maintenance items, including replacing cutting blades, drive and deck belts, and engine oil. If you find your machine has a bigger problem, use our service locator to find a qualified MTD service provider in your area.