Why Is Your Electric Lawn Mower So Loud?

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Willie writes on small engine repair, landscaping, and lawn care. He owned a professional lawn care business in Alabama for almost 10 years.

1. Loose Parts

Electric lawnmowers can produce a lot of noise if they have loose parts. The blades, motor, deck, and other lawnmower parts can become loose over time. These parts will produce a rattling noise when the lawn mower is running if you don’t tighten them.

The main reasons your electric lawnmower may develop loose components include:

Vibration: The blades and other parts of the lawnmower can become loose due to the vibration produced by the motor.
Age: The older your electric lawn mower is, the more likely it is to develop loose parts.
Use: If you use your electric lawn mower regularly, its different parts are exposed to wear and tear and may need servicing.
Running over hard objects: Lawn Mower blades become loose when they hit hard objects like stones or roots (source).

How To Fix

Fixing loose parts on your electric lawnmower starts by identifying the part. You must know which part is loose before developing an appropriate fixing method.

A simple way to identify the loose part is by paying attention to the noise. For example, if the rattling noise comes from under the deck, it’s most likely a loose blade.

Once you know which part is loose, you can fix it using one of these methods:

Tighten bolts and nuts: You should first check all the bolts and nuts to see if they are loose. If any of them are, use a wrench to tighten them.
Use lock washers: If your electric lawn mower has been producing a lot of noise recently, then it’s likely that the vibrations have caused the bolts and nuts to become loose. To prevent this from happening again, you can use lock washers.
Replace worn-out parts: If the part is too old or damaged, you may need to replace it entirely. It’s worth noting that you can’t tighten worn-out parts like bolts due to weak threads (source).

2. Dull Blades

Your electric lawn mower may be loud because the blades are dull. The blades won’t cut grass properly when they’re dull. This causes the motor to work harder, making the lawn mower louder.

Instead of cutting grass, dull blades tear it apart. The tearing also causes a lot of noise while destroying your lawn, leaving it unsightly and ragged.

In addition to making your electric lawn mower noisy, dull blades can also:

Reduce your lawn mower’s efficiency.
Cause the motor to overheat.
Damage the grass by tearing it instead of cutting it.

How To Fix

The only way to fix dull blades is to sharpen or replace them. However, you must ascertain that the blade is dull before sharpening it.

You can ascertain if the blade is dull by trying to cut a piece of grass with the blade. If it produces an excellent clean cut, then it’s not dull. Otherwise, the blade is dull and needs sharpening if the cut is ragged on the edge.

Here is the procedure you can follow to sharpen your electric lawnmower’s blade:

Switch off the lawnmower and unplug it from the power source.
Lift the lawnmower on its sides to locate the blade.
Use a piece of wood or anything to secure the blade as you remove it.
Use a spanner to unscrew the blade anticlockwise.
Once removed, use a file or grinding wheel to sharpen the blade.
Check the blade’s sharpness by trying to cut a piece of grass. It should produce a clean cut this time.
Reassemble the lawnmower and test it on your lawn.

The video below demonstrates how to sharpen an electric lawnmower blade:

How to Sharpen Electric Mower Blades : Lawnmower Maintenance & Repair

Watch this video on YouTube

If you don’t feel like sharpening the blade yourself, you can take it to a professional or replace it with a new one if it’s damaged.

Safety Tip: Always wear goggles, gloves, and long sleeves when sharpening your lawn mower blade, especially using a grinder. The blade can get sharp and cause an accident.

3. Bent Blades

A bent lawnmower blade hinders your lawnmower’s efficiency. Such a blade will damage your lawn’s appearance and the mower’s body parts.

Some of the signs that indicate a bent lawnmower blade include:

Strange noises: A bent blade produces grinding noises that can be irritating to work with. You’ll often hear these sounds emanating from the deck’s underside.
Uneven cuts: A bent blade produces uneven cuts since it doesn’t make contact with the ground evenly. The blade will also tear the grass instead of cutting it.
Vibrations: A bent blade produces vibrations that can be felt through the lawnmower’s handle. The vibration is usually caused by the blade hitting something hard, like a rock or a root.

Continued use of a lawnmower with a bent blade can damage its crankshaft.

How To Fix

Fixing a bent lawnmower blade can be challenging since it needs specific equipment. You need the following tools before embarking on repairing the bent blade:

Wire brush wheel
Blow torch
Angle grinder or metal file
A clamp or vice grips
Safety goggles
Protective gloves
Blacksmithing hammer or rubber mallet

Procedure

Flip the lawnmower on the side to access the blade.
Remove the blade by unscrewing it anticlockwise. Don’t try to hammer the blade while still attached to the lawnmower, as they will cause more damage.
Clean the blade using the wire brush wheel. Ensure to remove any grass or debris from the blade.
Check the blade for dings, dents, and bents.
Secure the good end of the blade using vice grips or clamp. You should leave the damaged end free to work on.
Heat the blade with a blow torch until it becomes red. This is to soften and make it easier to work on.
Place the heated blade on an anvil and hammer the bent area. Be slow while hammering to create a smooth and perfect surface.
Once the blade cools, use the angle grinder and wire wheel brush to sharpen it.
Check the blade for balance by inserting one finger where the bolt goes. The blade is balanced if it remains horizontal while you move your fingers up and down.
Reattach the blade to the lawnmower and test it on your lawn.

The blade should now be balanced and not produce grinding noises or vibrations. Take the blade to a professional for help if it still makes a loud noise.

4. Excessive Friction on the Moving Parts

An electric mower has the following components, which should move freely:

The blades: These are the parts that do the cutting. They are usually made of metal and are very sharp.
The wheels: The wheels help to move the mower forward or backward. They are usually made of plastic or rubber.
The motor: It powers the blades and wheels. It’s usually electric.
The gears: The gears help to transfer the power from the motor to the blades and wheels. They are usually made of metal.

The mower can be loud if any of these parts is not moving freely. This is because the part will rub against something else and create friction. The most common cause of this is a dirty or clogged mower.

How To Fix

The best way to fix this problem is to start by cleaning the mower. This will remove any dirt, grass, or debris causing the friction. You can use a garden hose or pressure washer to clean the mower. Be sure to wear safety goggles and gloves when cleaning.

You should lubricate the mower’s moving parts after cleaning.

Like any other machine, a well-lubricated lawn mower will run smoothly and not produce strange noises (source). The main parts that need lubrication are:

The transmission
The mower deck’s spindle bearings
The wheels’ axles

You can use a lubricant like WD-40 or grease to lubricate these parts. Be sure to read the manufacturer’s instructions before using any lubricant.

AtomLube Ultra Heavy Duty (link to Amazon) is an excellent grease for lawn mower parts. It’s a heavy-duty grease suitable for thermomechanical durability.

The mower should run smoothly and quietly after lubricating it. If it’s still loud, a more severe problem may exist that needs to be fixed by a professional.

5. Impact of the Blade on Hard Objects

It’s possible to come across hard objects like stones and roots when mowing. The blade can create a loud noise when it hits such objects. The impact can also damage the blade or other parts of the mower.

How To Fix

Avoid hitting hard objects when mowing: If you hit something, stop the mower and inspect it for damage. You should immediately take the mower to a professional for repairs if you see any damage.
Comb the yard before mowing: Seeing objects like rocks in tall grass can be challenging. To avoid hitting them, comb the yard with a rake before mowing. This will also help keep your lawn healthy.
Mow slowly: If you go too fast, you may not see objects in time to avoid them. Mowing slowly will give you more time to react if you see something in your path.
Maintain the lawn mower’s blade height: An ideal mowing height is generally between 3 and 3.5 inches. If the blade is run lower, it can damage the lawn and make the mower louder by hitting objects.

How To Use Your Electric Mower Efficiently and Avoid Loud Noise

Prevention is always better than cure, and this applies even to lawnmowers. It’s your responsibility to ensure your corded lawnmower is in excellent condition to avoid any problems. The following tips will help you use your electric mower efficiently and prevent it from being too loud.

Comb the Yard Before Mowing

The yard may have objects that can damage your mower’s blade. Such objects include:

Stones
Roots
Twigs

By combing the yard with a rake, you can remove these objects and avoid damage to the mower. This will also help keep your lawn healthy.

Mow When the Grass Is Dry

If the grass is wet, it can clog up the mower and make it louder. It can also damage the lawn mower’s blade by making it choose and spit out clumps of wet grass. This grass can damage your lawn if not raked immediately.

Maintain the Lawn Mower’s Blade

A dull blade will make your lawnmower work harder and be louder. It can also damage your lawn by tearing the grass instead of cutting it cleanly. Be sure to sharpen or replace the blade when necessary.

You should also maintain the mower deck to avoid rusting and other problems. This will help to extend your mower’s lifespan.

You can maintain your lawn mower’s blade by:

Sharpening it regularly
Replacing it when necessary
Cleaning the mower deck

Check the Tires

Tires can make the mower louder if they’re low. This is because the blade will hit the ground more often, causing a vibration that makes noise.

You should regularly check the tires’ pressure and fill them up when necessary if your mower has pneumatic tires.

The best way to check tire pressure is by using a tire gauge. AstroAI Digital Tire Pressure Gauge (link to Amazon) is a suitable option for lawn mower tires. It’s designed to maintain the correct tire pressure and reduce wear and tear.

Summary

An electric lawn mower can be loud for several reasons. The most common one is that the blades are dull or the mower deck is rusty. Other causes include hitting hard objects and not lubricating the moving parts regularly.

You can prevent these problems by maintaining the mower and using it properly. Be sure to comb the yard before mowing to avoid hitting hard objects.

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