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Can I Run a Generator Without a Load?

Hello folks and welcome to Today we will be taking a look at generators and if it makes sense to run these machines when there is no load connected to them. Generators themselves are a great tool to have around the home or for your business. I live in a small town about an hour or so away from the Kansas City area. We can get a lot of power outages during the winter season due to ice storms or blizzards. We can also get these in spring time due to severe storms or even tornadoes. Whatever the cause is having a generator on hand and ready to go can provide comfort during these power loss events.

The question though is should you be running these generators without a load? Now this is a bit different then idling your car. A generator should only be ran with no load if you are doing an initial diagnostic check to ensure everything is working as it should. At most this should be a few minutes and then the unit should be shut down or a load connected. Typically the closer you are to the maximum capacity of your generator the more efficient the machine will be. In some cases you could end up using double the fuel if you are at fifty percent capacity then when you are at one-hundred percent capacity. This is why it is so important to find a generator size that suits your needs. Bigger is not always better.

Running Without a Load

A generator should only be run at a low load for a maximum of fifteen minutes. If you continually run generators without a load connected then you can actively damage your generator. There are a variety of consequences that can occur when running at no or very low load. A few of these are:

When ran at low load the the engine is cooler then it normally would be at higher loads. This results insufficient temperatures to create an efficient combustion. This means that the diesel fuel that you are using is not completely burned resulting in increased exhaust emissions. In these cases when an engine is running at low load you will see a large amount of white smoke. This smoke is not only dangerous to inhale but is also bad for the environment.

Remember how we mentioned that the diesel fuel is not being burned completely due to low engine temperature? Well not only does this lead to more exhaust but it also leads to increased soot and remaining fuel to clog throughout the engine. These clogs could center around seals, rings, and other critical areas. These clogs do not just go away either. They will be there until you correct the situation. The good news is if this does occur on your machine you can clear this soot and fuel out of your system by running at or near maximum load for a few hours. This is when your generator is most efficient and this extra soot/fuel will end up being burned away due to the increased temperature flowing through the system.

The other big con here when running these systems at low load is the oil. Again, when ran at these low load amounts your engine runs at low temperatures which results in the contaminants accumulating throughout your system. On top of these contaminants clogging parts of the engine they also can end up getting mixed in with the engine’s oil. This will result in the oil being burnt off and increased wear on the engine due to low lubrication. As we all know, having proper oil levels for an engine is critical for operation. If your oil is being burnt up you will not only see the white smoke we discussed earlier but also a bluish smoke as well. Lastly, if you begin to see black smoke form then the fuel injectors are getting damaged as well due to no lubrication.


While all of the above are consequences that can occur when running your generator on low load there are also impacts that you will see when using your generator. These can be intermittent power losses and or poor performance from the machine. Eventually you will see parts of the generator fail and need to be replaced or maintenanced. If the unit is continually run at low load then the generator will eventually need to be completely replaced.

In conclusion, do NOT run your generator on load low. It is not good for your machine and will only result in further trouble down the road. I hope this article was able to answer your questions folks. Lastly, please note that this article is intended for informational purposes only. We here at ToughAssTools are not liable for any property damage or personal injuries that can occur when operating generators.

Thanks for reading,

Alec Johnson



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