Troy Bilt Mower Belt Keeps Coming Off

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If your Troy-Bilt mower belt keeps off, it might be due to a worn belt, damaged belt guides, loose pulleys, debris interference or a shredded belt.

Continue reading to learn more about the causes and solutions for a Troy Bilt mower belt that keeps coming off.

Ready? Let’s dive right into it:

Reasons Your Troy Bilt Mower Belt Keeps Coming Off

Some of the reasons why your Troy Bilt mower belt might keep coming off include:

  • Worn or loose Troy Bilt belt
  • Shredded belt
  • Damaged belt keepers
  • Faulty bearing in the spindle housing
  • Worn idler tensioner bracket or spring

Tools You Need For This Job

While troubleshooting, you might need to have the following tools nearby:

  • Hammer
  • Vice grips
  • Socket wrench 
  • New belt
  • Screwdrivers
  • Pliers

Troy Bilt Mower Belt Keeps Coming Off: Possible Causes and Fixes

1. Worn or Loose Troy Bilt Belt


Over time, the belt of your Troy Bilt mower can loose or become worn from normal use. This will further affect the functionality and performance of the mowing machine. 


  • If the belt is cracked, loose or worn or it has a shiny glazed appearance on it, it means that it requires replacement.


  • Replace the old belt with a new one.  

2. Shredded Belt


Your mower belt may become shredded and can break or come off the mower deck. 

Shredding can happen when the belt rubs against an object such as a bracket or belt keeper on the deck. Also, the belt can shred if you do not install it properly


  • Check if the belt is properly routed around the pulleys.
  • Inspect if the belt isn’t rubbing itself against the belt keepers or brackets. A shiny appearance or smooth spot is an indication that the belt is rubbing itself on a metal component.


  • You may replace the bushing on some brackets. If you can’t replace the bushing, you may need to change the bracket assembly. 

3. Damaged Belt Keeper

The function of belt keepers is to keep the belt in place. Although your belt won’t touch the guides, they protect the belt from slipping off the pulleys. 

They can become bent and defective, allowing the belt to come out of place.


  • Inspect if there is slack in the belt. If you notice an extra slack, the mower’s belt keepers may move out of place.


  • Use vice grips or a hammer to bend the belt keeper back in place.
  • Replace the belt keeper if it is in bad condition.

4. Faulty Bearing in The Spindle Housing

It is also important to check any bad bearing in the spindle housing if the belt keeps coming off.

A defective bearing in the spindle housing can make your cutting deck vibrate when you engage the blades. This vibration can cause the belt of your mowing machine to come off.


  • The first step to take is to get work gloves to shield your hands from the blades’ sharp cutting edges.
  • Rock the blade in an upward and downward position by grabbing hold of each end. While rocking the blade, check for any movement. If you notice a movement or you hear a knocking noise, it indicates that the bearing in the housing may be defective.


  • Replace the bad spindle housing.

5. Worn Idler Tensioner Bracket or Spring 

It is always important to check the idler tensioner bracket or spring if your mower belt keeps coming off.

The spring may be weak and the hole in the tensioner belt can also become larger and worn. This can cause the mower belt to fall off and affect the mower’s performance.


Check for worn idler tensioner brackets and the weak spring. If you notice signs of vibration in the mower, it means that you should replace the worn parts


Replace worn idler tensioner bracket or spring.

6. Bad Bearing in the Pulley

Bad bearings in the pulleys may cause the pulleys not to sit parallel and flat to your Troy Bilt lawn mower deck.

In this situation, the sides of the pulley may be higher than the other. This will make the mower belt not to run properly and can come off the pulley.


  • Rotate each pulley by hand to check for a bad bearing. Move them slowly to be sure that they are turning smoothly.
  • Check if you can hear a noise emanating from the bearing or if you feel any restrictions. If you detect these signs, then the bearing is bad. 


  • Replace the bearing in some pulleys. 
  • If you notice a bad bearing in an idler pulley, replace the entire pulley because it contains a sealed bearing.

7. Oil and Rust on Troy Bilt Belt

Oil can get onto the belt and cause it to stretch if the oil covers it for a long period, causing oil leakage. If the oil is covered on the belt, it can cause it to slip on the belts and come off your mower deck.

Another reason for this issue is rusty and old pulleys. These rusty pulleys can cause the belt to dry out, making it liable for breakage.


  • Check your mower for oil on the belt and rusty pulleys.


  • Repair the oil leak
  • Change the rusty pulleys and also replace the mower deck with a new belt. 

8. Debris in the Grooves of Your Troy Bilt Pulleys

The grooves in the pulleys collect mud or debris that can cause the belt to come off your lawn mower.

The pulley’s material may also cause the belt to stretch and this will allow it to snap or roll off the pulley.


  • Take a look at the grooves in the pulley and check for items (such as debris and mud) that are stuck in the area.


  • Examine the grooves in the pulley and take off any items that may be stuck in this area.

9. Debris Interference

The debris can accumulate around the tensioner and pulleys of your mower. This can hinder the proper movement of the pulley and can loosen the belt if it does not get enough tension. In this case, the belt can vibrate.

Debris build-up can also cause fire hazards due to the heat of the belt.


  • Check the belt for excessive vibration. If it vibrates, it can be a result of debris buildup.


  • Take off the debris thoroughly and clean it with a clean cloth. 

10. Troy Bilt Mower Deck Belt Breaks or Gets Heated Up

This is one of the problems that can be associated with your Troy Bilt lawn mower belt. If the belt breaks, it will come off the mower deck.


  • If you detect unsatisfactory cuts, turn off the engine of your Troy Bilt mower and check the mower deck carefully for any sign of belt breakage.


  • To fix a broken belt, you need to clean your mower deck, adjust the pulleys and replace the belt.

11. Extreme Weather And Temperature Can Cause The Belt To Come Off

Your Troy Bilt mower belt may keep coming off in extreme temperature changes. This issue is very common in very cold climes.

The reason is that the belt loses its shape in cold weather. If you continue to operate the mowing machine with this problem, It will produce cracks on the belt and break it.


  • Check for cracks on the belt to know if the belt is damaged. 


  • Do not operate the mower in extreme temperatures and weather. 
  • Replace the cracked belt with a new one.

12. Loose Pulleys

The belt connects a series of pulleys in the mower deck, which enables the mower blades to engage and spin.

If the pulleys are loose, the entire system would be compromised if the pulleys become loose in their positions.


  • Check the pulleys if they are not loose in their positions
  • Examine other parts of the pulley-belt system. If the parts are damaged or lost over time, it means that the pulleys are loose and the mower belt won’t stay in place.


  • It is advisable to seek the help of a trusted mechanic that can check the Husqvarna mower for defective or missing rear hanger clip pins and draft rods.

Tips to Extend The Lifespan of Your Troy Bilt Mower Belt


Here are some tips to follow to elongate the life of your Troy Bilt lawn mower belt:

  • Replace damaged belt keepers or brackets.
  • Always clean your Husqvarna cutting deck after mowing to get rid of debris.
  • Inspect the spindle housings and pulleys for bearing failure at periodical intervals.
  • Keep rust and oil from forming on your belt.

How To Tighten The Belt On a Troy-Bilt Riding Lawn Mower

Here are some tips on how to tighten the belt on a Troy Bilt riding lawn mower:

Step One: Gather the Required Tools

The first step to take is to gather the required tools to use. These tools include a socket wrench, screwdrivers and pliers.

Step Two: Get An Ideal Place For Belt Replacement

It is advisable to look for a flat and spacious area where you can easily do the whole work. You can use areas like a patio, driveway garage or a similar outdoor area that is ideal for your work. 

While you are in this area, place a plastic sheet on the floor to prevent oil or gas spillage from damaging your floor while working.

Step Three: Prepare the Troy-Bilt Mowing Machine

The next thing is to prepare your mowing machine for the task. You need to turn off the lawn mower. Ensure that you detach the spark plug cable and take off the spark plug to prevent the mower from starting.

Empty your mower’s gas tank and make sure that you have the oil dipstick tightened up to prevent any issue of oil leaks while working with the mowing machine.

Step Four: Take Off the Deck Cover

Take off the deck cover so that you can get the position of the belt. To remove the deck cover, you have to find the area of the mower’s frame and use a wrench to loosen the clamp bolts.

You can also use pliers if the wrench does not work. Carefully remove the deck cover. Ensure that you do not operate the metal part forcefully because it can bend.

Step Five: Take Off the Blade

Remove the mower’s retention bolt to take off the blade. To take off your blade, take off the screw that is positioned next to your rear tire.

Look for the retention blade and use your wrench to unfasten it. Detach your mower blade  freely.

Step Six: Expose The Mower Belt

If you want to tighten up the belt, you need to expose the belt. Locate the screws that are holding the engine baffle to your mower deck. Detach and take them off accordingly.

Take off the baffle that connects the mower blade with your engine. This will provide an access to the screw that secures the deck’s belt cover. Ensure that you remove the screw.

Locate the spring that is positioned between the belt cover and the transmission pulley and remove it so that you can take off the cover.

Step Seven: Adjust Your Mower Belt

To adjust the mower belt, you have to manipulate the engine pulleys and transmission. Check the cap screw which is in the pulley’s middle and unbolt it.

This will enable you to access the transaxle pulley. Manipulate and adjust the belt length. Your concern should be on shortening the belt’s length, so that the pulleys will be tight.

Step Eight: Reinstall Everything

Start by placing the belt cover in its appropriate position and also put back the engine baffle. Screw it in tightly and ensure that it does not fall.

Fasten your blade accordingly and ensure that you put the retention bolt in its proper position so that the blade can attach firmly.

Attach the deck cover again. Put the bolts and screws in their right place and tighten them properly.

Step Nine: Reconnect and Test

Ensure that you reconnect the wires and other components that you have previously disconnected. 

Connect the spark plug cable to the spark plug. If you took off the spark plug, screw in on the engine.

Refill your gas tank as necessary. Check if there are no issues with the oil and then, you can carry out the test.

Start your mowing machine and drive it around to see if it is working efficiently and smoothly. 


Some of the possible reasons why your Troy Bilt mower belt may keep coming off include shredded belt, defective belt keepers, faulty bearing in the spindle housing, bad bearing in the pulley and loose pulleys.

Follow the recommended troubleshooting guide and fixes to help you to solve the issue. If your mower does not work well after trying the troubleshooting tips shared here, it is best to call a technician.