Craftsman Riding Lawn Mower Blades Will Not Disengage: Fix

Craftsman riding lawnmowers make grass cutting quick and easy but wear and tear is incredibly common. For example, accidentally riding over a rock or other obstacle is all it takes to cause damage to the underside of the mower. One of the main issues with these lawnmowers is the blades not disengaging. This is usually the result of an issue with the idler arm, belt, return spring or PTO cable.

Fortunately, it’s possible to fix each of these issues at home. It is vital to know what you are doing when dealing with these problems as they could result in an accident if carried out incorrectly. This article includes step by step guides on repairing each of the potential causes so your lawn mower can be up and running again in no time.

To fix Craftsman lawnmower blades that are not disengaging requires removal of the mower deck, replacement of the return spring and repair of the engagement arm. If the deck and engagement arm are rusty then the whole unit may need replacing.

How To Fix Your Lawn Mower Blades Not Disengaging

Mower blades not disengaging has multiple potential causes and multiple fixes, the fixes listed below should help to rectify the problem. When you fix your lawn mower blades, proper safety is the number one priority. Always make sure the machine is off and disconnect the spark plug as an extra precaution.

Things You’ll Need

  • Wood blocks
  • Pliers
  • Rust cleaner
  • Handheld grinder

Idler Arm

The idler arm is in the center of the deck. When in working order, the arm moves and engages the blade. Remember that a rusty arm will not move as it should so keep an eye out for rust.

When you move the engagement arm manually it may catch and not return to its starting position freely. This part is crucial to being able to cut the grass, use the steps below to remove and replace the idler arm on your lawn mower.

Step 1. Take the Mounting Bolt Off

The mounting bolt is attached to the second pulley. Remove this bolt first as it will then give you access to the rest of the deck.

Step 2. Take the Second Pulley Off

After the removal of the mounting bolt, you can now carefully remove the pulley.

Step 3. Remove the Engagement Spring

You will now see the engagement spring. Remove this spring and put it to one side. If the spring is in good condition then it can be used again. However, if there is rust or the spring is bent then it is necessary to purchase a new engagement spring.

Step 4. Remove the Washers to Free the Arm

There are a few washers and a spacer holding the arm in place, remove these. These will be easy to see and should be simple to take off. After removal of these, the arm will be free to move.

Step 5. Take the Arm Off

You can now remove the arm. Inspect it for signs of wear and tear as well as any bends or dents. If the arm is slightly dented then use a handheld grinder to smooth it out. If there is rust or damage on the arm then the mower will need a new arm.

Step 6. Put the New Arm Into Position

Finally, put the repaired arm or a new arm into position. Most importantly, you need to put the washers, spacer, pulley and mounting bolt back where they were removed from. Take your time reassembling the mower and ensure each piece is properly secured.

Return Spring

If the blade belt is in the correct position, the issue could be the extension spring. If the spring is not attached to the end of the cable then it is not functioning and the blades won’t engage.  The spring may break on one side and this means the belt won’t tighten and loosen as it should. Fortunately, the spring is quick and easy to replace.

Step 1. Prepare the Mower

Firstly, switch the mower’s ignition off and remove the key. Park on hard, even ground and let the engine cool before working on the deck.

Step 2. Lower the Deck

Secondly, lower the deck to its lowest position and put the clutch actuator lever in the off position.

Step 3. Remove the Retaining Pins

With the deck now lowered, remove the retaining pins. Carefully detach the arms.

Step 4. Release the Deck Belt

The deck belt is the next part that needs to be carefully removed. The belt should slide out with ease. Put the belt to one side.

Step 5. Detach the Clutch Cable

Detach the clutch cable from the retainer. There may be locking tabs to release but detaching the cable takes just a few seconds.

Step 6. Slide the Deck Out

With the key components now removed, pull the deck out. It should slide easily. Then, use pliers to remove the spring.

Step 7. Install the New Spring

The spring is an integral part of the system and needs to be in good working order. A new spring is inexpensive but will help to make your mower work more effectively. Replacing the old spring with a new one will also help keep the mower well maintained.

Step 8. Slide the Deck Back Under the Frame

With the new spring in position, you can slide the deck back into position. After that, it is easy to put the clutch cable onto the retainer and realign the belt.

Step 9. Reposition the Support Arms

Finally, put the support arms into position and replace the retaining pin. The mower now has a brand new spring and the blades should engage.

Drive Belt

The drive belt can become loose, cracked, or frayed over time. In this step by step, we show you how to check the condition of the drive belt and how to replace it if necessary.

Step 1. Prepare

Firstly, park the mower and remove the keys. Give the engine time to cool and then lower the deck as far as it will go.

Step 2. Remove the Cable

Once the mower engine has cooled, remove the wire that runs down the centre of the deck. A cotter pin connects the wire so remove this pin so you can take the engagement cable out.

Step 3. Remove the Belt

The blade belt should now slide off easily. Just make sure you know what way it needs to be put back on before you remove it. Either check the manual or take a picture of its position and orientation before you remove it.

Step 4. Inspect the Belt

Most importantly, you now need to check the belt carefully for signs of wear and tear. A worn, broken, or damaged belt needs replacing while a dirty belt will simply need a good clean.

Step 5. Put the Belt Back

Ensure the engagement arm and pulley are in their proper positions then wind the belt through them. The belt needs to run between the retaining arm to avoid damage. Check the operator’s manual or your picture from earlier to ensure the belt is in the correct position.

PTO Cable

The PTO cable connects the engine of the mower to the deck and blades. There should be some resistance when you move the PTO lever.

Step 1. Park and Engage the Parking Brake

Firstly, park the mower and make sure it is safe to work on. Then, locate the PTO cable and inspect for damage.

Step 2. Remove the Battery

To access the PTO cable, first disconnect and remove the battery. There may be a bracket or clip that holds the battery in place so remove this first. Then, lift the battery out. Also, remove the battery supports so there is better clearance. After that, you can easily access, check and work on the PTO cable.

Step 3. Expose the End of the PTO cable

With the battery and battery supports removed, you can now locate the end of the PTO cable. After that, check the condition of the cable. Fraying and disconnection of a worn PTO cable is common with general wear and tear.

Step 4. Remove the Cable

Before you remove the cable, take a close look at how it is set so you can position it back properly later.

Step 5. Replace the Cable

Depending on the condition of the old cable, it may be necessary to install a new cable. First, hook the spring in place and then put the cable in where the old cable used to be.

Cutting Deck

Step 1. Park the Mower

Firstly, park the mower on a hard, flat surface. After you turn it off, wait for it to cool.

Step 2. Lower the Deck

Now, lower the deck. It’s a good idea to place supports underneath the deck to reduce the amount of pressure on the connector arms.

Step 3. Remove the Engagement Cable

The engagement cable is a metal wire that runs down the center of the deck. Remove the cable by taking out the cotter pin that holds it in place.

Step 4. Remove the Blade Belt

After that, remove the blade belt. This belt is the one around the main pulley system and should slide off.

Step 5. Unhook All the Cotter Pins

There are a number of cotter pins that hold the arms to the deck; you can remove these starting at the back and working forwards. Make use of the supports underneath to reduce pressure on the cotter pins so they are easier to remove.

Step 6. Lift the Engagement Arm

Finally, the engagement arm needs to be moved. Raise the arm and then you will be able to pull the cutting deck out. After that, you can inspect the cutting deck for signs of damage. If the deck is in bad condition, it may be worth investing in a new deck or unit.

Why Your Craftsman Riding Lawnmower Doesn’t Disengage

While the most common cause of a mower not disengaging is the idler arm, it could also be the spring, pulley, or PTO cable. The reason for this issue may vary but it will come down to one of these factors. As each of these parts works together it is easy to check their condition and determine where the problem is.

It’s best to start by checking the condition of the idler arm; it is normal for the regular engaging and disengaging of the arm to cause wear and tear. Maintenance is essential and the video below shows how to fix the engagement arm.

Tips When Repairing Your Mowers Faulty Engagement Arm

Clean the Rust

The cutting deck and parts will begin to rust if they aren’t regularly cleaned. However, rust can be cleaned by wiping each of the components on a regular basis. Pay attention to the deck components, for example the pulleys and washers, as it is common for these parts to begin rusting first.

Inspect All Deck Components

The deck has many elements that work together. Each of these parts play an important role so if one element is neglected it could cause other issues. Some parts, including the pulleys, are often overlooked. When repairing or maintaining the deck, don’t forget about these components too.

Keep Note of the Cotter Pin Locations

The cotter pins are important as they hold the deck and its components in place. When you remove the cutting deck there will be a number of cotter pins to take out. To make putting it all back together much easier, take note of the location of each of the pins.

Keep the Deck Clean

Many riding lawnmowers have a wash nozzle that lets you clean the deck with a hose. If the deck hasn’t been cleaned in a while it will likely need some extra attention as dirt quickly cakes on. In addition to the hose, an air compressor is a great way to remove debris without damaging the deck.


How long should a Craftsman lawn mower last?

A Craftsman lawn mower lasts 10-15 years if it is properly maintained.

How long is the belt drive on a Craftsman riding mower?

The belt drive on a Craftsman mower is between 42” – 50”, it varies depending on the specific mower model.

What kind of oil do you use in a Craftsman lawn mower?

SAE 10W-30 is the recommended oil for climates above 32 degrees Fahrenheit, colder climates should use SAE 5W-30.


In conclusion, a Craftsman lawnmower has a long lifespan but only if it is well cared for and regularly maintained. Keeping the deck and its components in good working order will help make sure the blades are disengaging properly. Issues with the blades need to be resolved as soon as possible as such problems could be very dangerous. Most importantly, the above fixes will help get the mower back in working order quickly and safely.