Generator Maintenance

When Should You Add Fuel Stabilizer to Your Generator?

Have you ever had issues starting your generator after extended months of storage? If you haven’t, you may have added a fuel stabilizer or were very lucky. For most generator owners, a month of storage without a fuel stabilizer means keeping the generator free of all the fuel, and still, there might be issues caused by the small traces left.

If you have never heard of a fuel stabilizer or use it but don’t know what it is or how it works, this post is for you. Its content describes everything you need to know about the formulated liquid.

What’s a Generator Fuel Stabilizer?

A fuel stabilizer is a formulated solution designed to provide a protective layer that sits on the fuel inside the fuel tank or storage can. It’s made primarily using petroleum products to bond with gasoline molecules to prevent evaporation and degradation. Some brands come with additives that help prevent corrosion and water build-up.

Why Use a Generator Fuel Stabilizer?

Gasoline is a mixture of many chemicals, hydrocarbons, and other additives. These chemicals make it volatile. Its volatility makes it break down over time when exposed to moisture and oxygen.

When the oxygen in the air comes into contact with gasoline, the metals start to oxidize. What you will be left with is gummy stuff with a nasty smell, what we call stale fuel.

What’s more, ethanol, one of the blended additives in gasoline, is hygroscopic. It can accumulate up to 49 percent water saturation. If that happens, it results in phase separation. The ethanol-water solution sinks to the bottom, thereby creating two layers.

When you start the engine, the water-ethanol mix layer is what the engine will pull first. It’s disastrous to the generator engine as it will cause it to run poorly, translating to inadequate power production.

What’s more, if the water-ethanol mix sat in the fuel tank for an extended period, it can corrode the fuel tank from the inside out, forcing you into a costly replacement.

Even if you store your generator with a fuel tank full, oxidation will still occur. It’s even worse today as modern gasoline contains a high percentage of ethanol. That means more water attraction which will accelerate the fuel breakdown.

High-quality ethanol-free gasoline can stay stable almost indefinitely with proper storage. The same can happen with high-quality gasoline stored in airtight containers in controlled humidity and temperature.

However, since both these options are costly and only feasible in commercial applications, your gasoline is bound to go ‘bad’ at some point.

How long does it take for fuel to go ‘bad’? Gasoline stays stable for at most 30 days. From here, it starts to degrade from oxidation. At some point, the fuel starts to varnish, and it’s left untreated. That’s when it starts to gum up and clog any openings in the generator fuel system.

That’s where the generator fuel stabilizer comes in – with a fuel stabilizer; the fuel is protected from the oxygen that oxidizes it to make it stale. The chemical adds a layer of protection to prevent vanishing and inhibit ethanol from pulling water from the atmosphere.

What Does a Generator Fuel Stabilizer Do?

As I mentioned in the section above, a fuel stabilizer prevents gasoline oxidation and breakdown. It bonds with the fuel molecules, coating and protecting them from oxygen exposure. That means there will be no more gumming or fuel evaporation.

While doing so, it also creates a protective layer on ethanol, the hygroscopic additive, preventing it from attracting water from the atmosphere.

By doing so, it eliminates the need to drain the generator fuel before storage. It also ensures you enjoy the convenience of an easy generator start next time you need the emergency power.

Understand that you cannot reverse stale gas. You cannot add a fuel stabilizer to turn ‘bad’ fuel into ‘good’ fuel. However, you can extend your gasoline’s shelf life when you add it at the beginning of the storage.

High-quality fuel stabilizers can keep your fuel fresh for even three years. However, it’s a must you store it properly.

When Should You Use a Generator Fuel Stabilizer?

A fuel stabilizer is mainly used when you’re not using or running your generator. If you plan to store your generator for more than a couple of days, you need a fuel stabilizer to protect the fuel and the generator fuel line.

And since generators are mainly used for emergency power, most people find themselves using the generator a handful of times in a year or season. That means, at a time point, the generator will stay in storage for months.

If you still want to preserve the fuel in the fuel tank or in a storage container to stay ready for the next disaster, it’d be best to treat it with a fuel stabilizer.

Usually, I advise generator owners to add a fuel stabilizer if they will store the generator for more than two weeks.

It’s okay to leave fuel in the generator for a couple of days when you’ve added a fuel stabilizer. If the storage might extend to more than a month, mix the fuel with the solution and drain every drop of the fuel in the fuel line to an ideal fuel storage container.

How Much Generator Fuel Stabilizer Should You Use?

Typically, the fuel stabilizer will come with instructions written on a sticker on its back or with a manual.

The instructions will have the amount of the solution you should add to a specific gasoline quantity. You don’t need much for a generator.

For example, you need one ounce (30mL) STA-BIL® Storage Fuel Stabilizer for 2½ gallons (9.5L) gasoline.

How Do You Add Generator Fuel Stabilizer

Adding a fuel stabilizer to a generator is upfront and straightforward. Here are the steps to follow:

When Storing the Generator with Fuel for Short Time:

Step 1: With the generator engine off and cool, shake the generator gently to check the level of fuel in your fuel tank if yours has no fuel gauge. Before adding the fuel, you want to make sure the tank is almost empty.

Step 2: Add the right amount of your ideal properly formulated fuel stabilizer into the fuel tank. If you don’t have a preferred brand, you can go for an STA-BIL® Storage Fuel Stabilizer. Read the manufacturer’s instructions for the dosage. Add clean gasoline to almost full and wipe any spills.

Step 3: Start the generator engine and run it for 10-15 minutes. This is to allow the treated fuel to travel through the carburetor and engine. It will help prevent gummy deposits and thus increasing the chances for easy after-storage generator starting.

When Storing the Generator without Fuel for a Long Haul:

Step 1: If your plans don’t include using the generator in the next 30 days, drain every drop of gasoline in the generator.

Start by setting the fuel valve to the OFF position and allow the generator to run out of fuel. Disconnect the fuel valve pipe and drain the fuel in the tank into a storage container.

Please do the same with the carburetor by opening the drain crew or bold on its bottom. Use the generator manual to locate it.

Step 2: Once the generator is empty and all the fuel is in a proper fuel-storage container, add the right amount of the Fuel Stabilizer, seal the cap and shake it to give it a nice mix.

Related Questions

Can Stabilizer cause a generator to produce smoke?

When you add a fuel stabilizer, it pulls water from the fuel. If there were some water at the fuel tank bottom, you would get a light white smoke. If it’s more than that, you may have a bigger problem. Check out my post on generator smoke. It should give you all the answers you may have about a generator producing smoke.

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Sharif Gen

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