Skip to Content

Lawn-boy Lawnmower Drive & Cutting Problems. With Fixes

It can be annoying when your routine garden chores are piling up, and the lawnmower doesn’t move. Most problems lawnmower users face are related to the cutting operation and handling. If you face such issues with a Lawn-boy lawnmower, this article will try to help you troubleshoot and fix them.

Lawn-boy Lawnmower Cutting & Drive Problems: Troubleshooting with fixes

If your lawnmower’s cutting performance has dropped, you should start by inspecting the blades. Check for blunt edges, wear and tear, and misalignment along the shaft, all of which can lead to poor results when it comes to cutting. In addition, wear and tear of the drive belt affects power distribution and results in the lawnmower getting stuck/not moving forward.

(CC BY 2.0) by dok1

So, if you’re a beginner or a seasoned user, this step-by-step guide will help keep your Lawn-boy lawnmower running smoothly for many years to come.

Lawn-boy Lawnmowers: Troubleshooting Cutting Problems

Inspecting and ensuring the proper functioning of mower blades and mowing deck is essential if you own a lawnmower. Failure to perform routine maintenance of the blade and its deck might cause cutting problems, such as those mentioned below. 

1. Lawn-Boy Lawnmower Doesn’t Cut Straight?

Straight-cust grass is important if you’re a garden lover or a professional gardener. If your lawnmower is not cutting straight, it could be due to the following reasons: 

– Unequal Tire Pressure: 

I recommend checking the tire pressure before any other component of the lawnmower fails to cut straight. Unequal tire pressure can cause the deck’s level to shift, resulting in some grass blades being cut unevenly than the rest.

Check the tire pressure with a tire gauge to confirm that all tires match the acceptable levels listed on the sidewall. Maintaining consistent tire pressure is needed for a smooth drive operation.

– Dull Blades: 

Cutting blades can get blunt over time, resulting in a worsening cutting performance. This is usually due to extensive use, severe wear from rugged terrain like sand or stones, or poor blade maintenance routine. Dull blades make mowing more challenging by decreasing the vacuum required for a clean cut. 

Regularly sharpening the blade edges with a bench grinder would be best. I recommend checking the blade’s sharpness before using your Lawn Boy Lawnmower. You can sharpen the blades without removing them, but I recommend removing them as this makes it much easier to check the balance.

– Unbalanced Blades: 

An imbalanced blade weighs more on one side than the other. This can occur due to irregular wear or blade damage. Also, excessive sharpening can result in metal unevenly removed from one side than the other. If a blade is dynamically unbalanced, it can vibrate excessively during rotation.

Excessive vibrations from unbalanced blades might lead to early degradation of the spindle bearings and a rough-cutting experience.

To check for blade imbalance, you can use a blade balancer tool. Or, you can hang the blade on a nail to ascertain which side is heavier and falls downward first. That side can be further sharpened until the blade is in balance.

However, particularly after more extensive blade damage, I recommend replacing the blade.

– Troubleshooting Spindle Bearings: 

If you hear squeaking noises while mowing and the grass is cut unevenly, there is most probably damage to the spindle bearings. To check the damage to the spindle bearing beneath the mowing deck, grab it from one end and move it back and forth. 

If you hear an audible knocking sound, it is undoubtedly a sign of a broken spindle bearing. If the bearing is faulty, replacing it is recommended. You can ask a mechanic for help to perform this replacement if needed.

2. Lawn-Boy Lawnmower Cuts Uneven Grass Patterns?

If a lawnmower cuts uneven patterns, it can be due to the following causes:

  • Dull Blades:  If the blades’ edges seem rounded or blunt after inspection, consider sharpening them. If the wear and tear is significant, replacing the blades is recommended.
  • Deck Height Adjustment: Make sure the deck is leveled at all four sides using adjustment screws. Follow the manufacturer’s recommendations to ensure the cutting height is set correctly. A level gauge can help make accurate changes to the deck’s height. 
  • Drive Belt Maintenance:  Checking and replacing Deck Belts is essential in preventing uneven grass patterns. Worn-out deck belts might affect cutting uniformity and generate vibrations during mowing. Inspect the deck belts regularly for wear indications and replace them as needed.
  • Inconsistent Mowing Speed:  Uneven grass patterns can be caused by fluctuations in mowing speeds. To obtain uniform and crisp grass edges, mow at a steady and level speed. Avoid rapid changes in cutting rate as it affects the cut quality.

3. Lawn-Boy Lawnmower Doesn’t Cut at All?

If your Lawn Boy Mover does not cut grass at all, follow the following steps to troubleshoot it:

1. Examine Blade Lever: 

The blade engagement lever must be activated to spin the blades. Examine the lever for any debris or grass clippings that might jam it and hinder correct engagement.

To guarantee smooth blade action, thoroughly clean the lower part of the mower deck and make sure all grass clippings are removed.

2. Inspecting the Blade Belt: 

A damaged blade belt might cause the blade to stop rotating. You must tilt the mower over and remove the mowing deck to access the blade belt.

Examine and replace the blade belt regularly if the teeth are worn or damaged.

3. Locked-Up Mandrel Assembly: 

The mandrel assembly contains the blade shaft and the bearings and is driven by the blade pulley. If the mandrel gets jammed due to debris buildup, the blades may not spin freely, affecting the cutting.

Misaligned bearings can also generate vibrations in the blade.

Tilt the mower over and remove the mowing deck to troubleshoot the mandrel. Remove the blade’s mounting bolts and the mandrel using a socket wrench.

You can purchase an identical one online by checking the part number or visiting your local dealer. Ask a professional for help if you are unsure how to fix the mandrel.

Lawn-boy Self-Propelled Lawnmowers: Troubleshooting Drive Problems

This section will discuss the most driving problems encountered with Lawn-boy self-propelled lawnmowers. Using the steps, you can troubleshoot and fix them:

1. Lawn-Boy Lawnmower Doesn’t Go Forward?

If your self-propelled lawnmower is unable to move despite the engine running, the following troubleshooting trips might help fix the problem:

a. Engage the Drive Control:

Start by checking the drive control lever or button’s position. Most users tend to ignore engaging the drive control lever, and the lawnmower doesn’t move.

b. Assess the Drive Belt: 

The drive belt drives the pulley, which engages the wheels. Inspect the belt by removing the mower deck and check the teeth for wear and tear. If the teeth are worn out, power transfer to the pulley would be reduced, and the lawnmower wouldn’t move.

Check if the belt is too loose. In that case, tightening can fix the issue. If the belt is damaged or worn, replace it.

c. Inspect the Wheels: 

If the problem persists, turn your attention to the wheels. Dirt and debris accumulated between the wheels and axle might hinder the wheels’ rotation.

I recommend removing all dirt and debris from your wheels and axle. Check that they are correctly mounted on the axle and can rotate freely.

2. Is the Lawn-Boy Lawnmower Throttle Not Working?

The throttle lever is used to control the engine RPMs and, in turn, the lawnmower speed. If throttle control doesn’t respond, try the following steps to resolve the problem:

a. Examine the Lever & Cable: 

First, check the lever to confirm it isn’t jammed. If it is difficult to move, use WD-40 or a lubricant to ease its movement. Do not forget to lubricate the cable as well.

Spray some WD-40 on the top or bottom, and move the cable ten times. That way, the lubricant can find its way to the whole cable.

Next, check if the cable gets tension when the lever is pressed. If the cable doesn’t move while the lever is used, the cable is likely to be broken.

b. Inspect the Carburetor: 

If the throttle lever moves correctly, but the engine doesn’t rev much or has a slow response, the carburetor might be the problem. Examine the carburetor jets for any old fuel residues. Use a reputable carburetor cleaner to clean the jets thoroughly.

Disassemble the carburetor, and clean the float bowl and bowl nut thoroughly. Test the throttle lever again after reassembly. In most cases, the problem should have been resolved. 

2. Lawn-Boy Lawnmower Vibrates Excessively?

Excessive vibrations are not only annoying but can cause damage to the spindle housing and the deck. The following factors produce vibrations:

a. Imbalance or Damage: 

Check for blade balance by holding the blade at its center. Unbalanced blades can cause vibrations throughout the mower at higher RPMs.

This problem can be solved by balancing or replacing the blade.

b. Loose Engine Mounts: 

Check for extreme engine vibrations that loose engine mounting bolts could cause. To prevent vibrations, ensure that all bolts are tightly secured, and none are missing.

c. Crankshaft Damage: 

Prolonged use under heat and excessive overrevving of the engine can result in crankshaft damage, which causes excessive vibrations.

This is an engine damage scenario, and this may require a new engine instead. I recommend asking a professional for help to determine if that is the case.

5. Lawn-Boy Lawnmower Is Leaking Oil?

A malfunctioning drain plug or a worn-out engine gasket is the most likely cause of an oil leak in your lawnmower.

A worn-out drain plug beneath the oil tank may also cause oil spillage. Avoid tilting the lawnmower with the air filter pointed downwards since this causes oil to flood into the combustion chamber from the crankcase.

Check the condition of the drain plug. Maybe it is loose or in bad condition. Keep the oil level at around 3/4 of the maximum to avoid overloading and subsequent leaks.

The second reason is more complex. Gaskets installed between the engine block and the cylinder head keep oil from entering the cylinder head. Gaskets can wear out due to thermal expansion, producing oil leaks over time.

Replacing the gaskets involves removing the cylinder head. This is a complex job. Ask a professional for help if you have never done this.

By following these troubleshooting tips and doing regular maintenance, you can easily maintain your lawnmower and enjoy a well-kept lawn. 

Drive & Cutting Troubleshooting table

1. Lawnmower Cutting Problems

Lawnmower doesn’t cut straight
a. Dull blades
b. Tilted mowing deck
a. Sharpen the blades using a grinder or a bench file.
b. Using a level, ensure the deck is perfectly horizontal.
Lawnmower cuts uneven grass
a. Blade vibrations
b. Faulty spindle assembly
a. Ensure the blade isn’t loose.
b. The blade should be balanced at its center. If not, it should be replaced. c. The spindle bearing should be replaced if it is faulty.
Lawnmower doesn’t cut at all
a. Disengaged blades
b. Debris/Grass clippings
c. Worn-out belt
a. Use the blade engagement lever.
b. Clean the spindle from debris and grass clippings.
c. Replace/adjust the blade belt as needed.

2. Lawnmower Drive Problems

Riding Lawnmowers

Lawnmower doesn’t move forward
a. Transmission disengaged
b. Faulty drive belt
c. No hydraulic fluid
a. Use the transaxle lever to engage the drive.
b. Adjust/replace the drive belt as needed.
c. Replenish transmission fluid.
The lawnmower has a loose steering
a. Loose tie rod ends
b. Damaged steering bushing
a. Tighten and lubricate tie rod ends.
b. Inspect and replace the bushing at the end of the steering shaft.
Lawnmower vibrates excessively
a. Blade imbalance/wobbling around the center
b. Damaged spindle bearing
c. Missing engine mounts
a. Tighten and adjust the blade to balance about its center.
b. Replace the faulty spindle bearing.
c. Tighten the engine’s mounting by adding fasteners.
The lawnmower has a flat tire
a. Low air pressure
b. Puncture by a sharp object
a. Purchase a puncture repair kit.
b. Apply the puncture seal and inflate the tire again.

Self-Propelled Lawnmowers

Lawnmower doesn’t move forward
a. Loose control cable
b. Worn-out drive belt
c. Debris locking wheels
a. Tighten the throttle control cable
b. Adjust/replace the belt as necessary.
c. Remove the debris from the wheels.
The lawnmower throttle not working
a. Defective throttle cable
b. Clogged carburetor
The lawnmower throttle is not working
The lawnmower pull cord is stuck
a. Damaged spiral spring
b. Damaged pull cord
Replace the damaged springs/pull cord.

Leave a comment

We try to answer each comment, but please read our comment rules first here. Use an existing and correct email address as you will receive an verification email. Your email address will not be published. All fields are required.

  1. Manuel Gutierrez says:

    How often should I replace the blade belt to prevent issues?

    • Web Editor says:

      Replace the blade belt annually for optimal performance and prevent problems in your Lawn-boy lawnmower. Regular maintenance is key to a smoothly running machine.

  2. Jonathan Hart says:

    What should I do if there is damage to the teeth of the drive belt?

    • Web Editor says:

      Inspect the drive belt for any wear or damage. If needed, replace it to ensure proper power distribution and movement. Regular maintenance is key to keeping your lawnmower running smoothly.

  3. Jerry Fernandez says:

    Can I use any blade balancer tool or is there a specific one for lawnmowers?

    • Web Editor says:

      Hi Jerry, for a Lawn-boy lawnmower, it’s best to use a blade balancer tool to ensure proper balance and avoid excessive vibrations. This will help keep your lawnmower running smoothly.

  4. Rhonda Rodriguez says:

    I had no idea unbalanced blades could cause early spindle bearing degradation.

    • Web Editor says:

      Thank you, Rhonda. It’s crucial to maintain balanced blades to prevent spindle bearing degradation. Regular blade maintenance is key to a smooth cutting experience.

  5. Salvador Hudson says:

    I didn’t know tire pressure affected cutting straight, good to know!

    • Web Editor says:

      Tire pressure is crucial for cutting straight with your lawnmower. Thanks for the comment, Salvador! Keeping all components in top shape will ensure a smooth mowing experience.

  6. Juan Collins says:

    How often should I sharpen the blades?

    • Web Editor says:

      “Blades should be sharpened at the start of each mowing season or after every 25 hours of use. Regular maintenance will ensure optimal cutting performance. Happy mowing!”

  7. Matthew Jenkins says:

    What’s the best way to adjust the deck height for an even cut?

    • Web Editor says:

      To adjust the deck height for an even cut on your Lawn-boy lawnmower, make sure the deck is leveled using adjustment screws at all four sides. Follow the manufacturer’s recommendations for setting the cutting height. Happy mowing!

  8. Elmer Miller says:

    How can I tell if the drive control lever is engaged?

    • Web Editor says:

      To engage the drive control lever on your Lawn-boy lawnmower, ensure it is pushed or pulled as directed in the user manual. This step is crucial for the mower to move forward.

  9. Hector Montgomery says:

    Do you have any tips for maintaining consistent mowing speeds?

    • Web Editor says:

      Thank you for your comment, Hector! To maintain consistent mowing speeds, ensure blade sharpness, check for deck level, inspect drive belts, and mow at a steady pace. Happy mowing!

  10. Michele Weaver says:

    How often should I check the engine mounts for looseness?

    • Web Editor says:

      Regularly checking engine mounts for looseness is essential to prevent excessive vibrations that can damage your Lawn-boy lawnmower. Inspect them at least once a season to ensure they are tightly secured.

  11. Nevaeh Watson says:

    Can I sharpen the blades myself or should I take them to a professional?

    • Web Editor says:

      You can sharpen the blades yourself, but make sure to maintain balance and sharpness. For more detailed instructions, refer to the blog post content. Happy mowing!

  12. Bryan Larson says:

    What tools do I need to troubleshoot the mandrel assembly?

    • Web Editor says:

      To troubleshoot the mandrel assembly on your Lawn-boy lawnmower, you will need a socket wrench and possibly a replacement mandrel. Remove the blade and mounting bolts to access the assembly.

  13. Claude Carr says:

    Is there a section on how to troubleshoot issues with the self-propulsion feature of a Lawn-boy lawnmower? It seems to be missing.

    • Web Editor says:

      Thank you for your feedback, Claude! I have added a section on troubleshooting self-propulsion issues with Lawn-boy lawnmowers. Check it out!

  14. Erika Cole says:

    Is there a way to prevent debris from jamming the blade lever?

    • Web Editor says:

      Hi Erika, make sure to clean the blade lever regularly to prevent debris from jamming it and hindering the blade engagement. This will help keep your Lawn-boy lawnmower running smoothly.

  15. Nathan Lambert says:

    Should I check the spindle bearings regularly even if I don’t hear any noise?

    • Web Editor says:

      Yes, checking the spindle bearings regularly, even if you don’t hear any noise, is essential to prevent future issues and ensure smooth operation of your lawnmower. It’s a good preventive maintenance practice.

  16. Darryl Roberts says:

    What is the best lubricant to use for the throttle lever?

    • Web Editor says:

      “Try using WD-40 to lubricate the throttle lever for smoother operation. This can help address any stiffness or sticking issues you may be experiencing. Good luck!”

  17. Riley Gibson says:

    Can damaged mandrel assembly cause the engine to stop?

    • Web Editor says:

      Yes, a damaged mandrel assembly can cause the engine to stop. It’s important to inspect and troubleshoot the mandrel if your Lawn-boy lawnmower is experiencing this issue.

  18. Marcia Elliott says:

    Is it safe to tighten the drive belt myself?

    • Web Editor says:

      Yes, it is safe to tighten the drive belt yourself. Just make sure to follow the steps mentioned in the blog post carefully. Good luck!

  19. Rene Allen says:

    I will definitely check the blade sharpness before mowing next time.

    • Web Editor says:

      Thanks for sharing, Rene! Checking blade sharpness is crucial for a clean cut. Remember to sharpen them regularly for optimal performance. Happy mowing!

  20. Danny Neal says:

    How do I know if a damaged blade belt is causing the cutting issues?

    • Web Editor says:

      Inspect the blade belt for wear and tear, misalignment, or damage. A damaged belt can lead to cutting issues in a lawnmower.

  21. Jack Hall says:

    How can I ensure that the wheels are correctly mounted on the axle?

    • Web Editor says:

      To ensure the wheels are correctly mounted on the axle, make sure they are free of dirt and debris. Regularly clean and inspect them to prevent any issues.