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Why Are Generators So Loud? – Here’s the Real Reason!

Written by Jamie Masterson

Usually, the more powerful the generator, the louder the noise.

However, sometimes they get louder than normal for many reasons such as insufficient oil, loose nuts, and wires, or an air leak.   

Here we will look into the different reasons that make generators noise and what you can do about it.

Why Are They Creating Loud Noises

1. Dirty carburetor

This is a common reason actually. When you store the generator with the carburetor loaded, the fuel turns into a gummy substance over time. This gummy fuel creates problems for the carburetor.

Note that this issue can develop within a week with only a few drops of fuel. That’s why you need to clean the carburetor regularly.

2. High load on the generator

When the pressure on the generator increases, the RPM (Revolutions Per Minute)  usually adjusts to it, which increases the engine’s noise. Most of the standby (emergency) generators work at 3600 RPM, which creates a loud noise.

Besides, home appliances like refrigerators with on and off cycles may also rev loudly.

3. Not choosing the right type of fuel

The engine may rev up and down, creating loud noise if you get the wrong type of fuel for your unit. In some cases, the generator may shut down completely.

Let’s say you’ve poured petrol into your diesel generator, which is a common rookie mistake. Now, you have to call professionals (The wrong fuel recovery service) to pump out the petrol before you can start using the generator.

4. Capacitor Failure

Has your old generator started revving up and down with high pitch noises? The most probable reason is a failed capacitor.
Check and replace the capacitor of your generator. Seek expert help if necessary. This should bring your generator’s noise down.

5. Not enough air or fuel

Every generator has to maintain a certain oil level to keep performing. The level varies from brand to brand.

In case you are getting a popping noise out of the unit, it would be wise to check both the user manual and the oil level of your generator. In case of a fuel-air shortage, restoring the right level will most probably solve your issue.

However, the problem still may persist. In that case, check the valves. The valves may generate sound if they’re stuck. Resetting the valves will solve the problem.

6. Some parts turned loose, broken, or dead

Another common reason behind a knocking or rattling sound is a loosen nut or a busted connecting rod bolt.

Damaged V belts can also create squealing buzz as well. A broken spring causes obstacles for the starter Bendix and generates a grinding noise.

Other worn-out components like tensioners, belts, and pulleys are also known to generate high-pitched sound.

7. Battery problems

All batteries have a limited lifespan and once that time is over, they can generate clicking noises.

If you find out that the source is your new battery, it may be defective and needs replacement.

8. Cables are defected

The irritating sound may also come from your cables if the connection is loose or if the cable is corroded.

Replacing the cable or tightening the connection may help resolve the problem.

9. Faulty ground connection

A ground connection is essential for your safety. Without a secure ground connection, you might get electrocuted accidentally.

Apart from that, a bad ground connection or a defective solenoid can also cause a bothersome clicking noise.

10. Vacuum leaks

In case you’re getting a high-pitched whistle noise, the most likely cause is an old worn-out belt or bad bearings or vacuum leaks.

We recommend seeking professional help since some of them can identify the problem just by hearing the sound.

Types of Generators

1) Portable generator

They are cheaper than standby generators but require manual operation. Additionally, you need to closely monitor them while they run. Some of them feature noise-reducing mechanisms but the power goes down with the noise.

2) Stand-by generator

This backup generator has the tendency of being annoyingly loud. It would be best to use them in a less crowded place. Usually, stand-by generators need dedicated housing to suppress the noise.

3) Prime generator

Prime generator installed in places where there is no electricity and continuous supply is required. They also produce a loud noise.

4) Stationary generator

Stationary generators are capable of producing a high power supply for commercial use. Usually, they produce the loudest noise and aren’t suitable for residential areas.

Which type makes more noise?

Portable generators are louder because they often do not feature a sound insulation system.

They are designed to function less than 12 hours in a row, mainly because loud noise for a short period of time can be tolerable, especially in case of an emergency.

However, we recommend not to buy portable generators for regular use. Otherwise, continuous loud noises will pose some serious health risks.

Standby generators also fall under this category.

How to Reduce the Noise level?

1) Do not place them on hard or rough surfaces like concrete or wood. Dirt or grass is a smart choice. If you don’t have a soft surface around then use an anti-vibration mat

anti-vibration mat

2) Build a soundproof generator housing or baffle box

soundproof generator box

3) Try to place your generator as far from your home as possible. Especially, the exhaust pipe should be far from your direction.

4) Change the muffler regularly

5) Sound deflector also reduces the noise to some extent

Sound deflector

6) As mentioned earlier, a more powerful generator will create more noise. Purchasing a generator more powerful than all your needs will be counterintuitive as the loud sound may create a bunch of health issues.

If you need to charge small devices like phones or tablets, a less powerful generator will not only do the job perfectly but also keep the noise down.


Q. Is 70 dB loud for a generator?

No. Generally, 60-70 decibel noise is a normal range for a backup generator. However, a portable generator may produce 100 decibels, which is definitely loud.

Q. Which generator is best – gas or diesel?

That depends on the intended purpose. We vote for diesel-fueled generators because they last longer than gas generators. Usually, an 1800 RPM diesel runs for 12 to 30 thousand hours before any major malfunction.

On the other hand, an equally powerful gas generator will provide 6 to 10 thousand working hours before facing a major malfunction.

About the author

Jamie Masterson

With decade-long experience as a generator technician, Jamie has worked with USA’s top generator manufacturers and suppliers as an independent contractor.

The long years of service to the industry has taught Jamie the ins and outs of troubleshooting, repairing, and maintaining all kinds of generators in home, industrial and outdoor settings.

Jamie thinks this platform is a great opportunity to share his tips and tricks with you so you can make the most of such power equipment for better living.

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