How To Adjust Lawn Mower Deck (Expert Advice)

Adjusting your lawn mower’s deck is an important part of maintaining your mower. If you don’t adjust the blade height on a regular basis, the underside of your yard can become uneven and unkempt. 

The process of adjusting a mower deck is relatively simple and can be done in less than an hour with basic tools and knowledge. 

Please note that this procedure applies specifically to riding mowers, not push or zero-turn models.

How the Pro’s Level a mower deck, Fix steering
Adjusting your lawn mower deck is incredibly important for maintaining a healthy lawn.
A poorly adjusted deck can result in uneven cutting which can damage the turf.
A level deck ensures the mower cuts grass evenly across the lawn.
Properly adjusted mower blades help prevent weed growth and discoloration.
Using the right tools and following expert advice can make it easy to adjust your lawn mower deck.

Measure The Length Of Cut Your Mower Produces

To measure the length of cut your mower produces, follow these steps:

Measure the distance between the deck and the ground. You should do this with your mowing deck in its highest setting.

Measure the distance between a straight edge (like a piece of wood) and the centerline of your blade, which should be parallel to it.

Now measure from one edge of that straight edge, along that same centerline, until you reach another point on it where there’s a gap between them (which will be right next to where they touch). 

This measurement should also be taken in inches and converted into decimal form if needed so that you can compare it accurately against other numbers later on (e.g., 0.75″ = .75″).

To achieve a well-manicured lawn, it’s important to adjust your lawn mower blades properly. A higher cutting blade can lead to weed growth and discoloration, while lower blades can damage the turf. Follow the expert guidance in our how-to guide about adjusting lawn mower blades to keep your grass healthy and vibrant.

Inspect The Spindle Housing Brackets

Inspect the spindle housing brackets for loose, damaged or missing parts. Check for bent or broken parts. Inspect the bearings for wear and damage. 

Check all washers and nuts/bolts for wear and damage. Inspect all hardware to ensure that it is tight and secure.

Table: Inspect The Spindle Housing Brackets

Inspection PointsObservations
Spindle housing bracketsCheck for any loose, missing, bent or broken parts.
BearingsInspect for any signs of wear or damage.
LubricationEnsure that the bearings are well-lubricated for proper functioning.
ReplacementsReplace any damaged or missing parts before resuming operation.

In order to maintain optimal performance and safety, proper inspection of the spindle housing brackets is essential. This table provides a summary of the key inspection points to help ensure that the spindle housing brackets remain in good condition.

Inspect The Blade Guard Bracket

You should also check the blade guard bracket to ensure that it is not damaged. If the blade guard bracket is damaged, replace it, and if it isn’t damaged and securely fastened to the deck, tighten the bolts.

Adding topsoil to an existing lawn is a great way to improve its quality and overall health. This is especially important for lawns that may have poor soil conditions. Our guide on adding topsoil to an existing lawn provides step-by-step instructions to help you achieve a healthier and more luscious lawn.

Inspect The Spindle Pulley

First, inspect the spindle pulley. The spindle pulley is the wheel that transfers power from the crankshaft to each blade. 

The pulley should have a smooth surface and should not be cracked or damaged in any way. If you find that your current spindle pulley is worn out, you may need to replace it before you can adjust your lawn mower deck.

If everything looks good with your old spindle pulley, then move on to checking for wear on the blades themselves.

Measure The Distance Below The Deck

To measure the distance below deck, use a tape measure and hold it up to your mower. Make sure you are looking at the blade, not the bottom of the deck.

The ideal height for grass is usually between 2-3 inches in height. If you notice that your lawn isn’t getting cut as well as it should be, there are several ways to fix this problem without having to buy an entirely new mower or blades.

First check if your blade is dull by removing it from its slot on top of your mower’s engine using an allen wrench (the wrench comes with most models). 

Inspect both sides carefully you’ll see signs of wear if they’re dulled down too much. A sharpened blade will cut through the grass more easily than a dull one; however, you can also adjust them yourself before changing them out completely!

If you’re starting from scratch, adding turf to your lawn can be an excellent option for creating an instant, beautiful landscape. Our guide on adding turf to existing lawn provides expert tips and advice for installing turf that is healthy, vibrant, and easy to maintain.

Adjust The Spindle Housing Brackets

Use a ruler and place it on top of the deck so that it runs between the spindle housing brackets and is parallel with the base of your mower.

If your ruler is longer than 1/8″ (3 mm) then you have too much slack in your mower’s belt drive system, which means that your belt may be slipping or not running tight enough to turn over its pulley wheels. 

If you find that there is less than 1/8″ of space between the ruler and deck, then that means that there isn’t enough tension in this area for the proper operation of your lawnmower

Table: Adjust The Spindle Housing Brackets

Step 1Place a ruler on top of the deck, running it between the spindle housing brackets.
Step 2Adjust the brackets until they’re at the same height, so the ruler is in complete contact with both brackets.
Step 3Use your hand tools to tighten the bolts on the bracket to make sure they stay in place.
Step 4Repeat the process on the other spindle housing brackets, if necessary.
Step 5Test the mower to ensure an even height adjustment.

Adjusting spindle housing brackets can deliver a cleaner, consistent cut for your grass. This table outlines the steps you need to take in order to properly adjust your spindle housing brackets for optimal cutting height and performance.

Install New Blades As Necessary

Install new blades as necessary. If you haven’t already done so, installing a new blade can make a big difference in the quality of your lawn. 

If you’re using a mulching mower, however, you’ll need to remove the old blade first before installing a new one (you can do this by loosening and removing two bolts).

Sharpen blades regularly: New blades will last longer if you sharpen them regularly with a file or sharpening stone this is especially important if you plan on using your mower more often than usual during the summer months.

Properly adjusting your lawn mower’s cutting height can go a long way in improving the look and health of your lawn. Our expert advice on adjusting lawn mower cutting height provides tips on setting the height of your mower to achieve a good balance of healthy growth, weed control, and aesthetics.

Adjust The Blade Guard Bracket

Once you have removed the belt and loosened the bolt from the blade guard bracket, you can adjust it.

Once it’s in position, tighten down on the bolts.

Replace Worn Or Damaged Parts, As Needed

  • Remove and replace the spindle housing bracket.
  • Remove and replace the blade guard bracket.

Replace the spindle pulley with a new one, if needed; you may need to replace this part if it is worn out or damaged in any way. 

If you are unsure whether or not you need to do this step, consult your owner’s manual for more information on how to determine whether or not your spindle pulley needs replacing before doing so yourself!

Replace your blades if they appear worn out or damaged (this can be done by simply loosening them).

Adding grass to your lawn can be a cost-effective option for improving the quality and appearance of your turf. Our landscape advice on adding grass to lawn provides tips on choosing the right type of grass and the best way to plant it for optimal growth and health.

Test Drive Your Mower

Test-driving your mower is a great way to check its performance, safety features and ease of use. 

You’ll also get a chance to see how well it was assembled, as well as detect any major problems that might have been glossed over during assembly.

Checking the mower’s performance involves checking whether your wheels spin freely and smoothly when you turn them by hand. You should also make sure that all of the controls are easy to reach and operate with one finger, including starting the engine (if it has an electric start feature).

Make sure that all safety features work properly not just those advertised on TV! For example, check for a kill switch (the button on many lawnmowers that kills power to the engine) or a disconnect mechanism (the lever that stops airflow through the carburetor). 

They may not always be accessible right away if you don’t know where they are located but rest assured there’s always one somewhere!

Ease of use is another important consideration; ensure there aren’t any switches or levers that take too much effort (“effort” being defined as “your arm starts shaking”) when operated under normal conditions; otherwise these could become hazardous when used during prolonged periods of time (such as during mowing).

Set The Deck To Its Lowest Setting

You should start by setting the deck to its lowest position. The mower should be started and allowed to run for a few minutes, then shut off.

This will ensure that all of the blades are in place and not broken before you start adjusting them.


Now you know how to adjust your lawn mower deck. If your lawn is looking a bit shaggy, or if it needs just a little more height, now is the time to bring out all of these tools and do some maintenance on your mower. 

It’s not hard at all; even with only one hand on my toolbox and another hand holding my phone as I search for instructions online, I was able to chop off an inch or two of my grass!

Further Reading

11 Simple Steps to Level Mower Deck: A step-by-step guide on leveling your mower deck.

How to Level a Riding Lawn Mower Deck: A comprehensive guide on leveling a riding lawn mower deck including important tips and tricks.

How to Level the Deck on Your Cub Cadet Rider: A specific guide on leveling deck on Cub Cadet riding machines that provides detailed information with clear images.


What does it mean to level a lawn mower deck?

Leveling a lawn mower deck means adjusting the cutting blade to sit parallel with ground to ensure an even cut across the turf.

What are the benefits of leveling a lawn mower deck?

Leveling a lawn mower deck ensures uniform cutting height, reduces scalping on uneven terrain and striping caused by unlevel cutting.

How often should a lawn mower deck be leveled?

A lawn mower deck needs to be leveled at least once every mowing season, or after any depression or bump that affects the deck.

What tools are needed to level a lawn mower deck?

Tools that may be required to level a lawn mower deck are wrenches, pliers, or adjustable pliers, and a measuring tape.

How can you tell if a lawn mower deck needs to be leveled?

One way to determine if a lawn mower deck needs to be leveled is to check the height of the lawn after cutting the grass. If height is uneven, then the deck may need adjusting.