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Your Belt Keeps Coming Off Your Snapper Lawn Mower (Solved!)

Your belt keeps coming off your Snapper mower. Having to keep stopping your mower and replacing the belt can get pretty frustrating. It’s time to find the reason your belt is coming off your mower so you can get back to mowing and not have to continually deal with your belt.

A Snapper mower belt can keep coming off the mower deck when brackets are bent or worn; the belt is worn or stretched; the bearings have failed in your pulleys and spindle housings; and debris caught in the deck affects your belt tension.

Take safety precautions before working with the components of your mower deck. Remove the key from your ignition switch and disconnect the spark plug wires to prevent your mower from starting. Wear gloves to protect your hands against sharp edges.

Belt keeps coming off your Snapper mower

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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing or operating. Consult a professional if you don’t have the skills, knowledge or are not in the condition to perform the repair safely.

9 Reasons Your Belt Keeps Coming Off Your Snapper Mower

  • Loose or worn belt
  • Belt keeper damage
  • Shredded deck belt
  • Bad spindle housing bearing
  • Bad pulley bearing
  • Worn tensioner bracket or spring
  • Debris interfering with belt tension
  • Debris stuck in the groove of the pulley
  • Oil or rust on the belt

Loose or Worn Snapper Mower Belt

A loose or worn Snapper mower belt can come of your mower deck pulleys. Belts wear with time from normal use. Replace your mower belt with a new belt when you see signs of wearing. This includes a belt that appears shiny, cracked or stretched.

Snapper Mower Belt Keeper Damage

Your Snapper deck uses belt keepers to assist with keeping the belt in place. The belt keeper is a rod that sits between 1/8” and 1/4” away from the pulley and is used as a method of prevention to keep your belt from coming off the pulley. The belt moves around your pulleys and doesn’t actually touch your keepers.

When you get slack in the belt, the belt can hit a belt keeper and bend it out of place allowing the belt to slip and come off your pulley. Fix your belt keeper by bending it back into place using a hammer or vice grips. If you can’t adjust it correctly, replace your belt keeper.

Shredded Snapper Mower Belt

If you notice shredding and torn edges on your mower deck belt, you must find the cause. Most likely, a bracket or belt keeper is out of place and your belt is rubbing against it causing the belt to shred. Another reason your belt can shred is when it is incorrectly routed around your pulleys.

First, make sure your belt is correctly installed. Refer to your operator’s manual or a parts diagram for the correct position of your belt around the pulleys. Second, find the item your belt is catching on when your deck is engaged. Look for a shiny flat spot on a belt keeper or bracket. This is an indication you have an area rubbing against a piece of metal.

Once you identify the part that is causing your shredded belt problem, adjust the part so it no longer rubs. If you find the cause happens to be a bracket with a bushing, you may be able to replace the bushing. Sometimes you must replace the bracket assembly when Snapper only sells the part in this way.

Bad Bearings in the Pulleys on a Snapper Mower

A pulley may no longer sit flat and parallel to the mower deck when the bearing is bad. A pulley with a bad bearing can cause the one side of your pulley to sit higher off the deck than the other. When this happens, your Snapper belt is more likely to come off the pulleys.

Check each of your pulleys to make sure they rotate smoothly and without restriction. Do this by slowly turning each pulley by hand. You will need to replace your pulley when you feel a restriction or hear a noise coming from your bearing.

Bad Bearing in the Spindle Housings on a Snapper Mower

Much like a bad bearing in a pulley can cause your pulley to not sit flat, a bad bearing in your spindle housing can allow vertical movement in a blade that can cause the deck to vibrate. This vibration can cause your belt to come off your Snapper lawn mower.

Before you work under your deck, confirm your ignition key has been removed and the spark plug wires are disconnected for safety. Wearing a good pair of gloves, grab a hold of each end of your mower blade and rock it up and down.

You will need to remove your spindle housing and check for bearing failure when you feel movement or hear a knocking sound. Replace a failed spindle bearing.

Snapper Mower Idler Tensioner Bracket or Spring is Worn

Wearing of the idler tensioner bracket and spring can happen over time. This is the bracket that holds your idler pulleys in line. The spring can become weak or break causing your belt to come off your Snapper. The hole where your spring attaches can also contribute to your spring and problem of adding vibration. Replace a worn bracket or spring.

Debris Interfering with Proper Tension on Your Snapper Mower Belt

Debris can collect on top of your Snapper mower deck and interfere with the movement of your tensioner pulley. Your belt can become loose when sufficient tension is not kept on your belt causing it to vibrate and come off your Snapper mower.

It isn’t only important to keep the belt area of your mower deck clean and free of debris for performance reasons, it is also important for safety reasons as well. Dry debris collected on the top side of your mower deck can catch on fire from the heat of the belt.  

Find out more details on cleaning your mower deck in my articles on cleaning your lawn mower and finding and fix mower deck problems. A clean mower will not only improve performance, but it can also extend your mower’s lifespan.

Debris in the Grooves of Your Snapper Mower Pulleys

Check the grooves of your pulleys for any objects that have gotten caught in them. This could be a small piece of bark, stone or even packed mud. Any additional material collected in your pulleys causes the belt to stretch around this additional material. It can cause your Snapper belt to roll off your pulleys or snap and break.

Oil or Rust on Your Snapper Mower Belt

Your Snapper belt can become covered in rust or oil from rusty deck components or an oil leak on your mower. Oil on your belt can cause your belt to slip and come off the mower. Rust will prematurely dry out your belt causing it to be more likely to break.

It’s important to fix the cause of the oil leak or rusting problem before you replace your deck belt with a new one or you will run into the same problems. Mower belts are expensive so you don’t want to keep on replacing them if you can prevent it.

Identify your oil leak and make the necessary repairs on your Snapper. It’s a good idea to regularly check your engine oil level before each use so you can identify any oil leaks early and prevent engine damage.

Clean the rust off your pulleys and deck. If the rusting is bad on your pulleys, you should replace them.

In Summary

Snapper deck belts can be pricey so the longer you can make them last, the better. Here are a few items that can extend the life of your Snapper mower belt to keep it from prematurely wearing or breaking and coming off your mower:

  • Clean your mower deck after each mowing to remove debris
  • Check for rubbing on deck components
  • Keep oil and rust from forming on your belt
  • Periodically check your pulleys and spindle housings for bearing failure
  • Fix or replace any damaged brackets or belt keepers