13 Reasons a Bad Boy Lawn Mower Has a Bad or Uneven Cut

You were excited when you purchased your new Bad Boy mower. Your lawn looked great with each mowing. Now, it’s disappointing when you find the mower you invested in no longer gives you a nice quality cut.

Continuing to run your mower with a bad cut is not an option. It’s time to figure out what is causing your uneven cut.

A Bad Boy lawn mower may have a bad or uneven cut when the mower deck doesn’t sit level because of low tire pressure, an unleveled deck, or a damaged deck shell.

An uneven cut can also be the result of worn, dull, or bent mower blades; spindle housing damage; a worn mower deck belt; or incorrect operating procedures.

Before you begin working on your Bad Boy mower’s cutting problem you must take the following safety precautions:

• Remove the ignition key and disconnect the spark plug wires to prevent your mower from starting.
• Never reach under a mower deck while the engine is running. Always wait for all moving parts to stop.
• Use heavy work gloves to protect your hands from sharp blades.
• Refer to your owner’s manual for additional safety procedures specific to your Bad Boy mower model.

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

Reasons Your Bad Boy Mower is Cutting Uneven

Low Tire Pressure

When checking for the reason your Bad Boy mower is cutting uneven you need to first check your tire pressures. When you have a low tire, your deck will not sit level.

Don’t skip this step. If you do, you may end up making unnecessary adjustments to your mower that you will have to eventually reverse once you realize your tire pressure is low.

Use a tire pressure gauge and check your tire pressure. The pressure for the tires on each side of your mower should be the same. If needed, correct your tire pressures. Refer to the manufacturer’s recommended tire pressure located on the tire sidewall.

Worn or Dull Mower Blades

Dull or worn mower blades can be the cause of an uneven or bad cut. If you are not regularly sharpening and replacing your mower blades, they can become extremely worn. The ends of the blades can become rounded leaving uncut grass between the blades.

The sail of the blade can also experience wear. The sail is the high side of the blade that is used to create air movement under the deck.

When the sail becomes worn, it can no longer create good air movement to form a suction under the deck needed to stand the grass tall for a nice cut.

You are not able to prevent a blade from wearing. This happens under normal conditions from the impact of sand swirling under the deck. Not only does the suction created by your blades and deck stand the grass tall, but it also draws in a lot of dirt that can wear the blade edge and sail.

I like to start each season out with a new set of blades and then regularly check and sharpen them throughout the season. It makes no sense to buy a nice mower and not find the time to take care of your blades.

While you can usually sharpen your blades several times before having to replace them, you must replace your blades when you realize the tips have become round or the sail becomes thinner than the center of the blade.

Bent Mower Blade

The mower blade spinning at high rates can bend when it impacts a solid object like a tree root or a rock. Not only can this bend the blade, but it can also damage the spindle housing.

To prevent this type of impact, take time to walk your lawn and remove anything that your mower blade may hit.

There are a couple of different ways you can check for a bent blade. Before you remove a mower blade, it is a good idea to quickly check the condition of the spindle and bearing. Refer to the section on the spindle housing below.

Check for a bent blade with the blade on your mower

With your mower parked on a flat level surface. Measure the blade end from the ground to the blade. Record the measurement. Rotate the blade 180 degrees and measure from the same spot in the ground to the blade end. Record the measurement.

If you find your mower blade has more than a 1/8” difference between the two measurements, your blade is bent and should not be reused.

Check for a bent blade with the blade off your mower

For this step, have a good blade you can compare each used blade against. Place the used blade on top of your good blade and look for gaps or bend in the blade that shouldn’t be there. Do not reuse a blade that does not sit flat against the good blade.

NEVER ATTEMPT TO STRAIGHTEN & REUSE A BENT MOWER BLADE. Doing so can put you and others in an extremely dangerous position.

Bending a mower blade back into position will compromise the metal, making it weak and more likely to crack. A blade spinning at very high speeds that breaks off puts people in the area at risk of injury.

Unbalanced Mower Blade

An unbalanced blade is a blade where one side of the blade is heavier than the other. This can happen from uneven wearing from normal use. It can also become unbalanced when more metal is shaved from one side of the blade during the blade sharpening process.

An unbalanced blade can cause your blade to wobble when it rotates under the mower deck. At very high speeds, the blade can cause spindle bearing damage. A significant vibration will be sent through your Bad Boy mower.

You can check the balance of your blade before installing it on your Bad Boy mower using a blade balancer. This is an inexpensive tool that can prevent you from damaging your mower.

If you don’t have a blade balancer, you can place a nail in the wall with the nail head about 1 inch away from the wall. Place the center of the blade onto the nail.

A balanced blade should sit level. If one side sits lower, you must shave a little metal off that end until the blade sits level on the nail.

Damaged Spindle or Bad Spindle Bearing

A damaged spindle or bad bearing can cause extra movement in your blade so it wobbles when it rotates. This can cause a significant vibration at high speeds and provide you with an uneven cut.

To check for damage in the spindle housing, with your mower blade still attached to your spindle housing, grab each end of the blade. Rock it up and down to check for any movement. You’ll also hear a knocking sound when your blade moves up and down.

When you experience movement or a knocking sound, remove your mower blade and take apart your spindle housing. Replace any damaged parts.

Plugged Mower Deck

Earlier, I mentioned the importance of the sail on your mower blade. It is used to create air movement under the deck to create a suction. The deck is designed to maximize the space under the deck for air movement to create a good suction for a nice cut.

When your Bad Boy mower has a mower deck that is packed full of grass clippings and yard debris, it reduces the amount of space available for good airflow and suction.

A plugged mower deck will not only give you an uneven cut, but it will also cause strain on your mower’s engine.

Keep your mower deck clean and free of debris. Scrape the deck regularly to prevent excessive buildup. To minimize buildup under the deck, avoid mowing in wet conditions. Wet grass will clump and stick to your deck.

You can attempt to use a spray to reduce the amount of buildup under the deck. Just understand, no spray is going to prevent all debris from sticking. It will only minimize it.

Mower Deck is Not Level

A deck that is not level can give you an uneven cut. When one side of your deck sits lower than the other, the mower may give you a stair-step kind of cut. Because adjustment procedures for leveling your Bad Boy mower deck vary by model, refer to your operator’s manual for leveling procedures.

Makes sure your deck is level from side-to-side and front-to-rear. Note: on some deck models, the front of the deck sits slightly lower than the rear. Again, refer to your owner’s manual for the exact specifications for your Bad Boy mower deck.

Deck Belt is Bad

A Bad Boy mower deck belt that is worn will fail to grip your pulleys and turn your blades at high speeds. A reduced blade tip speed will compromise your cut quality. Inspect your belt and look for signs of wear.

This includes a glazed shiny appearance or cracks in the belt. A stretched belt that doesn’t sit tight to the pulleys or one that sits deep in the pulleys is also a sign of a worn belt. You must replace a worn belt with a new one.

Bad Bearing in Your Pulley

The bearings in your pulleys on the Bad Boy mower can become bad. This can cause your pulleys to not sit flat and securely on the deck. There may be some vertical movement in the pulley causing one side of the pulley to sit higher off the deck than the other side.

To check for a bad pulley bearing, slowly spin each pulley by hand. Feel for a restriction and listen for bearing noise. When you experience either of these symptoms, replace your pulley.

Engine Speed is Too Low

When you engage your mower deck, you must have your Bad Boy mower running at full throttle. You need the engine speed to be at its highest to be able to send enough power to the mower deck to spin your blades and give your lawn a good cut.

You may be running your Bad Boy mower and realize your engine is no longer giving you the power required to cut your lawn.

If this is happening to you, have a small engine mechanic check and perform tests on your engine to identify any potential problems causing your engine to not give the power you need.

Moving Your Mower at Fast Speeds

Your engine can get overloaded when mowing at fast speeds causing your mower to give you a bad cut. Just like I mentioned above, an engine that doesn’t give you enough power can result in a bad mower cut.

Know your mowing conditions and adjust your speeds accordingly to not bog down your engine. When mowing tall, wet, or thick grass, you must operate at slower speeds.

Additionally, slow down when operating on hills. Mowing at too fast of speed can cause your mower to not cut all the grass or end up pushing it over instead of cutting it.

Incorrect Overlapping of Paths

Overlap your mowing paths to not leave strips of grass between each pass. If you have a new mower, this can take some time to get right.

You want to space your paths so you can save time and not keep mowing over the same section twice. It takes a little practice with your mower to get it just right.

Mower Deck is Damaged

If you accidentally run into a fence, tree, pole, or another item, you can damage the deck shell. This can give your mower an uneven cut if it is not corrected. If you are unable to fix your deck shell, you will have to replace it with a new shell.

If you need a deck shell replacement, I recommend contacting your Bad Boy mower dealership and getting a quote for a replacement deck along with the labor charge to swap all the components over to a new deck shell.

Compare this with a complete deck replacement. You may be surprised to find there isn’t a large price difference. With these two price quotes, you can make the right decision for you based on price and your Bad Boy mower’s condition.