SeaFoam vs Stabil Fuel Stabilizer for Storage

Last Updated on March 17, 2022 by Grow with Bovees

When you put your cars, boat motor or garden machinery in storage for any length of time such as over the winter,  you may be wondering if you need to drain the fuel tank first to prevent fuel related engine problems when you start them up again.

Without using a quality fuel stabilizer to keep the fuel fresh, that would certainly be the case, but by using one of these popular fuel treatments, you can leave the gas in the tank and not worry about it going off or causing issues for up to 2 years!

Two of the most popular choices for fuel stabilizers are Sta bil vs Sea Foam, and they can be used for treating the gas in cars, trucks, lawnmowers, etc. as well as anything you have in gas cans for emergency use.

We’ve compared them for use in different situations to find out which is the most suitable for you so that you can go out and buy just what you need.

Seafoam vs Sta-bil – Quick Comparison

Both these products will help prevent fuel contamination by moisture, stabilize fuel, increase storage life and also help clean your engine and entire fuel system in use, but they do have different strengths and uses. Here’s a quick rundown:

Sea Foam Motor Treatment

  • Stabilizes both gas & diesel fuels for up to 24 months, great for winter storage
  • Helps keep fuel injector and carburetor parts clean
  • Helps improve fuel economy
  • Cleans engine chamber and intake valves deposits
  • Liquefies harmful deposits & residues in crankcase oils
  • Lubricates and treats upper engine cylinders
  • Can be used for any blend of gas and diesel fuel
  • Does not provide significant protection from corrosion
  • Suitable for all conventional and synthetic motor oils
  • Not a glycol-based fuel stabilizer

STA-BIL Storage Fuel Stabilizer

  • Keeps gasoline fuels stable for long term storage – up to 24 months
  • Cleans carburetors and fuel injector components 
  • Helps improve fuel efficiency
  • Prevents gum and varnish build-up ensuring quick and easy starts
  • Works for both non-ethanol fuel and ethanol-blended fuels (up to E-85)
  • Prevents corrosion on internal surfaces of the fuel tank and engine
  • Not suitable for use in diesel fuels
  • Can be used for all gasoline engines including vehicles, generators, motorcycles, boats, and two-cycle engines
  • Not a glycol-based fuel stabilizer

A Closer Look at STA-BIL Fuel Stabilizer for Storage

Claiming to be “America’s #1 Fuel stabilizer Treatment”, Stabil has been around for over 60 years and is widely considered to be the most authentic fuel stabilizer for stopping stored fuel going bad. It’s now made by Gold Eagle who acquired the brand in 1986, introducing the now instantly recognizable double-necked bottle.

Several fuel system additive products are available under the Sta-Bil brand, including the 360 Protection range and the famous Storage product that we are looking at as part of this review.

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Their ‘Storage’ petroleum-based fuel stabilizer product is great for ensuring an easy engine start after being stored for a while by keeping fuel deterioration to a minimum and reducing evaporation. The additive is also great for keeping the fuel fresh during those times when you are just using your vehicle or machinery occasionally and not filling up very often.

By removing water from the fuel, STABIL Storage prevents corrosion and also contains a mild fuel system detergent to keep the carburetor and fuel injectors in great shape. It also prolongs the life of the engine by preventing the buildup of fuel residue, varnish, rust, and gum, so is great for long-term use.

Although the ingredients of fuel stabilizers are kept secret, the treatment does not contain any alcohol and is formulated with a powerful mix of chemicals and a combination of fuel additives that neutralize acids to help prevent oxidization of the fuel.

It also coats internal engine surfaces and inside the fuel tank to reduce corrosion.

Just one treatment will eliminate the need to drain the gas out of any two or four-cycle engine prior to storing.

How to Use STA BIL Fuel Stabilizer

Although it’s safe to use fuel stabilizers all the time, Gold Eagle recommends that you get the best out of the product by using it when you’re planning to store your gas-powered equipment or vehicles for 30-days or more.

Treating gasoline with fuel stabilizers will keep the fuel fresh for up to 2 years and is effective in all gas types (but not diesel) including Ethanol-blended varieties up to E-85 to help prevent ethanol-related fuel issues.

Just 1-ounce (30 milliliters) will treat up to 2½ gallons of fuel (9.5-liters). Using a stronger mix of up to 4 times the strength is absolutely fine as the product is petroleum-based and mixes well with gas.

It’s best to use fresh fuel pulled from the pump for the maximum benefits as older untreated gas will have started losing its volatility already, and no additive can bring that back.

Run the engine for around 5 minutes to ensure all fuel systems have been treated and then top up the gas tank to roughly 95% capacity. This helps to avoid condensation build-up in the gas tank whilst it’s being stored.

Sea Foam Motor Treatment Review

The Sea Foam product range has also been around for decades and was first introduced in 1942 although the creator, Fred Fandrei, a petroleum industry salesman, first came up with the idea in the 1930s.

Sea Foam is a fuel treatment that is a little different from Sta-Bil, in that it’s designed for everyday use in any type of fuel including ethanol gas blends and diesel, plus it can be used to treat the oil in your crankcase. It can also be used as a stabilizer product for fuel storage, just like its competitor.

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The motor treatment contains no harsh chemicals or additives, just petroleum-based fuel stabilizer lubricants and fuel system cleaners that are completely safe to use in your engine and fuel tank and works well as an ethanol fuel treatment.

The cleaning capabilities of Sea Foam are what really sets this apart from the other product as it has been shown to successfully clean intake valves, carburetor passageways, and fuel injectors as well as take care of engine chamber deposits.

Of course, the other big difference is that it can be used for diesel fuel engines and gasoline fuel engines as well as motor oil. It really is a great all-rounder and can help prevent the evaporation of diesel fuel.

One thing to note is that this product does not provide much in the way of protection from engine damage due to corrosion on internal engine surfaces, unlike Sta bil which is very good for that.

How to Use Seafoam Treatment for Motors

As Sea Foam can be used for engine cleaning and lubrication as well as storage, the dose rate and treatment will vary depending on what you need it to do.

As we’re comparing it with the Stabil fuel additive product on how well it works as fuel stabilization for storing, let’s take a look at how much stabilizer you need to add and when so that we get a similar idea of how to use it.

Like the competing product, it’s best to start with fresh fuel that’s just been pumped at the gas station to get the best results.

Again, as with Sta-Bil, dosing does not need to be that accurate.

Is Seafoam a good fuel stabilizer?

For stabilizing the fuel for up to 2 years, add Sea-Foam at the rate of at least 1-ounce to a gallon of fuel and then run the engine for approx 5 minutes so that the formula works its way through the entire fuel system.

For additional protection, adding more of the product when the tank is low first will boost the cleaning and lubricating properties by making the solution a stronger mix. You can then top up with more field and seafoam to finish prep for storing weedeaters, chainsaws, or any other type of gas powered equipment.

The manufacturer has full information on their website for when you want to use it as more of a fuel system cleaning product or oil additive to help improve fuel consumption and clean off deposits and other fuel system residues.

What do fuel system stabilizers do?

All fuel can go stale over time. In fact, gas in the fuel tank can start turning into varnish in as little as 30 days and the last thing you want is to start an engine that has contaminated fuel in the tank!!

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A petroleum-based fuel stabilizer slows down this process by delaying oxidization, which is what makes the fuel turn bad and become “gummed up”. Many formulas such as Sea Foam also help remove moisture from the fuel to help prevent water contamination which causes rust and corrosion, especially in older and antique cars.

This is especially true with an ethanol-blended fuel as the alcohol attracts moisture from the air, which can cause a lot of damage inside your engine and fuel tank.

You don’t need them if you’re using non oxygenated gas. Non ox gas is already designed to outlast winter, so rest easy.

Do I need fuel stabilizer for my lawn mowers?

Garden machinery such as a boat motor, lawnmowers, chainsaws, leaf blowers etc. are often winterized as they’re not usually needed during the winter months, so adding fuel stabilizers like Sea Foam to the gas will save you from having to drain the fuel tank and protect the engines at the same time.

Pour the treatment into the gas can and mix it with fresh fuel first, regardless of the fuel oil mix ratio, and then use that to load up your garden equipment to around 50% capacity.

Run them for 5 minutes or so to make sure the formula gets through the whole system, and then top up with the treated fuel so that the tank is around 90% full. This will help prevent condensation from forming in the tank whilst it’s in storage.

Is Sta-Bil or Sea Foam a Glycol-Based Fuel Stabilizer?

Choosing a petroleum-based fuel stabilizer that does not contain any glycol or other alcohol-based additives is important.

As with most fuel formulas, although the exact ingredients of fuel stabilizers are kept secret, both manufacturers have confirmed that our review products definitely do not have any glycol in them.

What should you use? Sea foam or STABIL Storage?

Now you know about Seafoam vs Stabil, you can judge which is better for your application.

Both products are great and if used as directed by the manufacturer will help keep your fuel and equipment in good shape when it’s not being used for a long time.

StaBil Storage is specifically designed for this purpose and contains a rust inhibitor, so we recommend that, if you are just after something that will keep your gasoline fuel engines and fuel good for up to 2 years whilst protecting your fuel tank.

Sea Foam is the better bet if you want something that is also going to clean the engine as well or if you need to treat diesel or diesel fuel engines. Note that its corrosion inhibiting properties are not as good though.

Whether you choose Sta bil vs Seafoam, or vice versa, neither product is a glycol-based fuel stabilizer, and it’s important to never use that sort of product for storage.