Not only is it important to use the right kind of gas in your generator, but it’s also important to know what can negatively affect fuel and how to care for it.

A portable Generac Generator uses unleaded gasoline with a minimum octane rating of 87 and a maximum ethanol content of 10%.

When working with fuel, always work in a well-ventilated area. Follow all precautions found in the Generac operator’s manual.

Gas for portable Generac generators

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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing, or operating.Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

Choose the Right Gasoline for a Generac Generator

When sourcing fuel for your Generac generator, it is important to use fresh gasoline with a low ethanol content. I also recommend using a fuel additive to help minimize the negative effects fuel can have on the fuel system and engine.

Low Ethanol Content

Ethanol is an alternative fuel that is added to gasoline so it is a little environmentally friendly. This product is often made from corn or another high-starch plant.

Ethanol naturally attracts moisture. This moisture and ethanol combination can leave behind varnish that coats and gums the fuel system causing fuel restrictions. It may also prematurely degrade generator components.

Because of its negative effects on the fuel system, always choose gasoline with an ethanol content no greater than 10%. The lower the ethanol level, the better. Never use fuels sold as E15, E30, or E85. These fuels contain up to 15%, 30%, and 85% ethanol.

Use Fresh Gasoline

Gasoline can begin breaking down as soon as 30 days after purchase. Because of this, it’s best to purchase fresh gasoline and consume it within this time.

If you purchase more gas than you can use within 30 days, add a fuel additive to stabilize the gas so it lasts a little longer before it begins to break down.

Add a Fuel Stabilizer

Add a fuel stabilizer to gasoline while it is still fresh. Fuel additives cannot reverse the effects of old gas.

I like to add Sea Foam Motor Treatment to every tank of gas. Sea Foam not only stabilizes gas but also cleans the fuel system and reduces moisture. It helps minimize problems that can develop from running old fuel.

Another good fuel additive alternative is STA-BIL.

Ethanol-Free Fuel (Optional)

Using an ethanol-free gas will avoid the negative effects ethanol has on the generator. While ethanol-free gas is better to run through your Generac, it is the more expensive fuel choice.

Ethanol-free gas can be purchased at some fuel stations. It is sold as recreation fuel or REC-90. It can also be bought in canisters at your local hardware store or online like this 4-cycle fuel by TruFuel. The canisters are a convenient option to have on hand.

Tips for Purchasing and Storing Gas for Your Generac Generator

Using the wrong kind of gas or old gas in a Generac generator can cause starting and running problems. Follow these quick tips when choosing and storing gas:

  • Always use fresh gas and consume it within 30 days.
  • Use unleaded gasoline with a minimum 87 octane rating and a maximum 10% ethanol content.
  • Add a fuel stabilizer when you are unable to consume gas within 30 days.
  • Store gasoline in a dry cool location away from combustible products.

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