Why Are Lawn Mowers so Loud?
Noise Source and Solutions
The baffles live inside the muffler and sometimes break free causing a thin metallic sounding rattle.
Mufflers get really hot and vibration can cause them to crack.
They can be repaired by your local muffler shop.
Gaskets are used to mate the muffler to the engine.
They create a seal, and as you can imagine when it breaks down you get lots of noise and fumes.
Gaskets are easy to replace.
Mower blades cut through the air like helicopter blades.
So if you think about it, if a mower blade could spin without an engine, the mower would still be pretty noisy.
The underside of mower decks are just painted, so debris gets thrown against it and it resonates, like a bell.
If only there was something we could spray on it.
You can DIY this one, at the auto parts store you can buy spray on bed liner which adds sound deadening and metal protection to your deck.
Just make sure the deck is clean and dry before painting outdoors.
Valve train will be noisy if their is excessive lash.
Most small engines don't have coolant they are air cooled and so they need a fan to pull cool air across the engine, and fans are noisy.
Keep all the metal to metal links well greased, it helps dampen rattling and squeaks.
Check that the rubber hood and seat stops are in place.
Super Quiet Lawn Mower Mufflers
Some makers do a better job than others, John Deere mufflers do a first class job.
Lawn Mower Louder Than Usual
Blade spindles transfer the the power to the blades. They are bolted to the deck and have bearings top and bottom to provide smooth spinning.
The bearings wear out and can cause a howl roar when the blades are on. The bearings can be replaced, but often replacing the whole spindle makes more sense.
Pulleys are used to drive and route belts around the chassis. Most will have bearings and they're the ones that cause trouble.
They're a common source of noise. Generally, if you have a worn out belt, then chances are one or more pulleys are also worn, and vice versa.
Pulleys are fitted to the driving belt and also to the cutting deck belt system.
Belt wear or damage will cause a cyclical noise as the damaged area contacts the pulleys.
Damaged cutting deck belts will also cause lots of vibration.