Is It Bad to Run a Generator Out of Gas? (No! Learn Why?)

A generator is a good source of energy during tropical storms and blackouts. If you are not living in an off-grid farmhouse or you are not going to RV trips or Camping regularly, probably you don’t need the generator all year.

So, you need to learn the basics of storing your generator safely.

Running a generator out of gas is a myth to the non-technical person. Probably, you believe that it is a bad practice to run the generator out of gas! And it will make damage the generator engine!

Contrary to the popular belief, running a generator out of gas will not damage your engine or parts. This practice usually damages the Pump (fuel pump, injector pump) that lubricates by the oil. Gas generators do not resemble pumps. 

Moreover, this is good practice to empty the gas chamber while storing the generator for further use. If you will not run your generator for more than 2 weeks, then you should preserve your generator in a systematic way.

In this article, I have elaborately discussed everything in running a generator out of gas. Since the answer is opposite to the traditional belief, keep reading attentively. I hope you will be cleared after reading this article.

Is It Bad to Run a Generator Out of Gas

Why Isn’t It bad to Run a Generator Out of Gas? 

You might be wondering about the answer. But this is the truth. If it is a diesel engine, your engine and parts may be damaged if you run it without fuel. You know, the gasoline generator doesn’t have a fuel injector pump. So, there is no reason to damage the gas engine. 

Why Is It a Good Practice? 

You should run your generator out of gas just before storing it. Running out of gas makes your carburetor dry. Ethanol has corrosive features.

So, if you are going to store your generator for more than 2 weeks, there is a high chance of corrosion on the carburetor. As a result, your generator will not start. 

So, it is recommended to drain out all the fuel from the engine before storing it. 

Interested in the Inverter generator? Read more about the best 1000-watt inverter generator.

Why Is It Bad for Diesel Engine? 

If you have a portable generator with a diesel engine, you should not run your generator out of diesel. The diesel engine has an injector pump. If there is no oil in the pump, the fuel injection pump will get primed and will cause a problem during the next start.  

run a generator in garage

Frequently asked questions 

What Happens If the Generator Runs Out of Gas During the Night?

Your generator will be stopped if the generator runs out of gas during the night. That is why you should be careful running the generator at the night. 

If it is a portable gas generator, then there is no problem with engine damage or something like that. learn more about how long will your generator run continuously.

But if you have a portable diesel engine, you should be careful. Because you know, it is harmful to practice for your generator and household appliances. 

How Long Can You Leave Gas In a Generator?

You can leave gasoline in your generator for a maximum of 6 months. You should not leave gas in the generator for more than this period. If you want to keep the gas in the generator for more than 6 months you could add fuel additives. Then you can use this fuel for more than a year.  

Can I Use Old Gas In a Generator?

Old fuel is not recommended for the generator engine. Old fuel is the enemy of the engine. 

There is no guarantee that you will face a problem by using the old fuel. But in most cases, people fall into the problem with the old fuel, like the generator takes time to start and others. 

Risks of Leaving Gas in a Generator 

Here are some common risks of leaving gas in the generator. Don’t forget to consider this point before leaving gas in the generator. 

Absorption of water 

Gasoline is Hydrophobic. Hydrophobic means a negative attraction. That means, Gasoline doesn’t want to bond with the water. 

On the other hand, Ethanol is Hygroscopic. Ethanol tends to bond with water. They have a strong co-relation. 

If you have a gas generator and keep gas in the generator for a long time, ethanol will bond with nature’s water. In the tank, water will be in the bottom and the ethanol will be on the upper surface. 

That is pretty dangerous for the engine. 


Oxidation is responsible for metal rust. Keeping gas inside the tank may cause rust issues in the tank. Moreover, it will degrade the quality of gasoline. 


So, long story short, you should run a generator out of gas. Though it is contrary to traditional belief, it is good for the gas generator. if you want to store your generator for more than 2 weeks, you should empty the gas chamber of the engine. 

In the case of the Diesel engine, it is the opposite. You should not empty the tank. The diesel engine has a pump system. So, oil is mandatory for engine health here. 


Rayan is an engineer, lives in a farmhouse. He has a passion for electronics and alternative energy. He loves to share his thoughts with other people. That is why he started the blog.

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