If like me you love mowing your lawn but hate the noise, you might be wondering how to reduce lawn mower noise.
To reduce lawn mower noise, you can try options such as tightening all the screws, replacing the muffler, changing the engine oil, adding mass to the deck, and fixing the blade assembly.
In this article, I’ll look at why exactly lawn mowers make so much noise, along with the best ways to make them quieter. None of these are particularly complicated so should be easy for you to do at home.
Why Are Lawn Mowers So Loud?
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Let’s be fair: not all lawn mowers are created equal. Some are much louder than others in the first place, and this only gets worse with age and wear.
What’s more, lawn mowers aren’t designed to be quiet machines. Very few lawn mowers designers have ever considered noise levels when designing their product, as their main focus is to function.
But why are lawn mowers so loud? Like all machines, lawn mowers have lots of moving parts in their engines. Electric lawn mowers are generally quieter, but they can still make plenty of noise.
Also read: Why Are Leaf Blowers So Loud?
As the engine ticks over, it vibrates. These vibrations travel through the lawn mower’s body and turn into sound waves. So along with the noise, the engine makes directly, you also have to deal with the sound of the body rattling.
A standard lawn mower operates at around 90dB, which is loud enough to cause damage to your ears when exposed to it for too long. This is reason enough to want to make your lawn mower quieter.
Over time, wear and tear to the machine will often cause it to make more noise. Screws can come loose, causing parts to rattle more, and things can get stuck or be broken.
Some of the most common issues that cause it to make more noise are:
- A cracked or broken muffler
- The blade assembly has come loose
- There’s a build-up of debris under the deck
- You haven’t changed the engine oil in a while
You can avoid all of these by regularly inspecting and maintaining your lawn mower. Ideally, you should solve these problems before they start making noise, as this can be a sign of damage.
These issues are characterized by clunking, knocking, or squeaking noises, so if you hear any of these be sure to get it checked out.
I’d recommend giving your lawn mower a thorough inspection before you start trying to reduce the noise it makes. The last thing you want to do is cover up a sign of a bigger problem.
How To Reduce Lawn Mower Noise
Once you’ve checked your lawn mower over and are aware of any signs of damage, you can move on to making it quieter.
Some of these options are about noise reduction but others are simple fixes for these common problems. I’d recommend starting with these and then moving on to the other options if you don’t get the results you want.
1. Tighten all the screws
Loose components rattle more than they should, which increases the amount of noise coming from your machine. Start by giving it a once over and tightening all the screws you can find.
You might need to remove some parts of the body to expose the inner workings, but it’s worth checking all of this over for loose screws before putting everything back together again.
2. Fix or replace the muffler
A muffler is a device fitted onto an exhaust pipe to deaden the sound that escapes from it. It contains several chambers and insulation to reduce noise but also increases engine pressure for greater efficiency.
The muffler on your lawn mower will break over time because it’s put under reasonable stress. Any cracks or gaps will allow sound to escape, which reduces its effectiveness.
There might also be damage to the gasket seal that sits between the exhaust and the muffler, which also allows sound to escape.
Follow these steps to inspect the muffler:
- Unscrew the exhaust pipe, only when the lawn mower is completely cool.
- Remove the exhaust so you can access the muffler, which might be hidden inside the lawn mower’s body.
- Undo the mounting bolts so you can remove the muffler entirely.
- Inspect it for signs of damage, both inside and outside. Cracks may only show on one side, so check both.
- Any minor cracks can be fixed with something like FiberFix (Amazon), which is specifically designed for this.
- If you see any signs of rust or any cracks that look fairly deep, replace it with a new one.
- Now is also a good time to fit a new gasket.
- Check the exhaust pipe for damage before replacing too.
If you need to replace the muffler with a new one, shop around for the best option. Longer mufflers reduce noise levels more than shorter ones, so this could be a good idea if you want a quiet lawn mower.
3. Change the engine oil
As with all engines, you need to change your lawn mower’s engine oil regularly to keep it in good working condition. The oil lubricates the engine’s moving parts but can become clogged with debris over time.
Change the oil each spring and possibly in fall too depending on how regularly you use the lawn mower.
- Oil changes are best done shortly after the operation because warm oil flows more easily.
- Put the lawn mower on a raised surface and angle it on its side.
- Locate the oil fill cap and put a pan underneath.
- Remove the cap and allow the oil to drain out. This takes a few minutes.
- Fill with new engine oil (amazon). Brands intended for cars are usually fine for this purpose, but the owner manual will give you the right information.
Pay attention to the old oil as it drains out. If it’s particularly dark or full of debris, this can be a sign of bigger issues inside the engine. It might be a good idea to take it to a specialist.
4. Add mass to the deck
The deck is the part that sits over the blade and is usually made of plastic. It’s not designed to be particularly soundproof, which you’ll likely notice if you ever run over a stone.
You obviously can’t soundproof the blades directly because you’ll stop them working, but you can add more mass to the deck. This will dampen the noise you hear coming from the blades underneath.
I’d recommend using either mass loaded vinyl or car sound deadening mats (Amazon links) for this job. Both will be fine, but sound deadening mats might be the better option because they have an adhesive backing.
- Tip the lawn mower on its side so you can see the blades underneath. It might be worth removing the spark plug so it doesn’t turn on.
- If you can use water, spray the underside of the deck with a hose to loosen the grass build-up.
- Use a scraper to remove all the grass and debris underneath. This will reduce the amount of noise it makes.
- Turn the lawn mower right side up and clean the top of the deck to improve adhesion.
- Cut your sound deadening material to size. Small panels will be easier to fit around awkward shapes.
- Stick the mats down, making sure to not get in the way of any moving parts. You can add more than one layer if you want.
The idea here is that adding more mass to the deck means it won’t vibrate as much while also deadening sounds coming from the blades underneath.
5. Fix the blade assembly
A loose blade assembly can cause plenty of rattling noise when operating. Over time, this might cause damage to the lawn mower too, as things aren’t where they’re meant to be.
- Remove the spark plug from the engine and tip the lawn mower on its side.
- Use a wrench to test the bolt holding the blade in place.
- If it’s loose, jam the blade in place using a piece of wood and then tighten the bolt.
If this doesn’t fix the problem then your blade might be out of balance. This happens over time and means it won’t spin efficiently. Luckily this is really easy to solve with a blade balancing tool (Amazon).
6. Buy a new lawn mower
This option might be a bit of a cheat, but it’s definitely the easiest way to make your lawn mower quieter. Upgrading from your old lawn mower to a new one will mean a more efficient machine and no wear and tear.
Your best option for quietness is an electric lawn mower. These have the advantage of not using a petrol engine, which means less noise and less vibration.
The main limitation used to be power cables, but you can now get ones with rechargeable batteries. I’d highly recommend investing in one of these to solve your problems.
Some Final Thoughts
As you can see, there are a few options for how to reduce lawn mower noise. The best thing I can recommend is to regularly maintain your machine, including monthly inspections and regular oil changes. This ensures you catch any issues before they become noisy and damaging.