The last tank of the season decides the first start of the next
Ethanol Shield keeps the last tank fresh — for up to three years
One ounce of the blue-shield stabilizer, a short run to move it through the lines, and the mower, the boat and the gas can all sleep through winter without gumming, rust or water trouble.
Price lives at our partner storefront and can shift by the time you land there.
Made in the USABlended in Conway, South Carolina
3-year stabilizationFuel stays burnable season after season
OEM tested & usedVerified by equipment makers
Top ASTM & NACE marksIndependent lab corrosion ratings
Three shelves in the shed
Every bottle on the wall
Six ways to buy the same promise — fuel that starts. Sizes for a single mower, a marina or the whole street.
What one ounce is doing in there
Holds water down
A phase-separation inhibitor keeps the ethanol in E10 from grabbing moisture and falling out of the blend — raising the water a tank can tolerate from .53% to .57% in modified ASTM E1064 testing.
Slows fuel aging 6×
Untreated E10 went unstable at 240 minutes in ASTM D525 oxidation testing. With the shield in it, the same fuel held past 1,500 — more than six times longer before gums and varnish start.
Blocks corrosion
A triple all-metal anticorrosive package earned the top 1a copper-strip grade in ASTM D130 and the highest NACE rating for ferrous metals — brass, bronze and steel all under the same shield.
Numbers off the lab bench
6×longer oxidation stability (ASTM D525)
5 / 5NACE corrosion resistance rating
1abest copper-strip grade (ASTM D130)
30 PPMnitrogen — top-tier detergent cleaning
240 galtreated by a single 24 oz bottle
One bottle, four pours
The cap is the measure. Pick what you are fueling and pour accordingly.
1 oz per 2.5 gallons
For mowers, trimmers, saws, ATVs and every small gas engine that runs weekly — pour into the tank or the gas can and just keep fueling.
1 oz per 1 gallon
The last-tank dose. Pour, then run the engine a few minutes so treated fuel reaches the carburetor and injectors before the machine parks for the season.
1 oz per 10 gallons
For cars and trucks — one capful rides along with a fill-up to keep ethanol-blend pump gas from working on the fuel system between drives.
1 oz per 5 gallons
The marine formula's cruising dose. Boat tanks breathe damp air all season; the shield keeps that moisture from settling in as a layer of trouble.
The shield advantage, shelf by shelf
| What the formula carries | Gasoline | Marine | Marine + MIB kit |
|---|---|---|---|
| Stabilizes fuel for up to 3 years | ✓ | ✓ | ✓ |
| Phase-separation inhibitor — water held in check | ✓ | ✓ | ✓ |
| Top-tier P.E.A. detergent for carbs and injectors | ✓ | ✓ | ✓ |
| Bonds 2-cycle oil to ethanol-blend premix | ✓ | ✓ | ✓ |
| 3X all-metal anticorrosive package | — | ✓ | ✓ |
| Doubled antioxidant load for the long sit | — | ✓ | ✓ |
| Octane stabilizer with upper-cylinder lubrication | — | ✓ | ✓ |
| Cleans out varnish, carbon and gummed fuel systems | — | — | ✓ |
| Covers diesel engines as well as gas | — | — | ✓ |
Treated tank vs. untreated tank
| Through a winter in the shed | With Ethanol Shield | Straight pump gas |
|---|---|---|
| Starts on the first pull in spring | ✓ | ✗ |
| Fuel still fresh after 12+ months | ✓ | ✗ |
| Carburetor free of gum and varnish | ✓ | ✗ |
| Water held safely in suspension | ✓ | ✗ |
| Rubber and plastic lines conditioned | ✓ | ✗ |
| Metal protected from ethanol corrosion | ✓ | ✗ |
Built for whatever burns gas at your place
Mowers & tractorsweekly runners and once-a-year starters
Saws & trimmers2-cycle premix stays bonded and fresh
Boats & outboardsthe marine blend for the long sit
Generatorsready the night the lights go out
Motorcycles & ATVspark in November, ride in March
Classic carsstorage fuel that will not varnish
Crew notes from the listings
This is a must have for todays fuel. If you run any seasonal Small engines like a snowblower, weed wacker, chainsaw, etc this is a must-have.
— mark, crew note from the product listing
Read an article about this product; decided to try it. Put it in the 11 gal tank that had about 3 gal left in it. The boat has been setting just under a year and started up first crank.
— Dennis Scott, crew note from the product listing
This fuel stabilizer out shines all others by a mile. I'll never use anything else. All my 2cycle engines run so much smoother and start easier too.
— Wayman E Nordstrom, crew note from the product listing
Great product. I've been using this product for years. My string trimmers, chain saws, generator, mowers all start up after winter storage. No carburetor or seal issues at all.
— Biddys Dad, crew note from the product listing
I use this stuff for gas treatment for everything. The stuff just works. Mowers, boat, trimmers, chainsaw, etc. It's a way better price when you buy a gallon! I recommend.
— Be Kind Rewind, crew note from the product listing
One of the best fuel additives I've ever used. It removes water from your gas. Helps to remove carbon from your engine, and cleans the deposits from your carburetor!!
— Harmony, crew note from the product listing
From the bench
Why pump gas goes stale — and what ethanol has to do with it
E10 fuel can start breaking down in about a month. Here is what phase separation actually is, and why the fix happens at fill-up, not in spring.
Read at the bench →Putting equipment away for winter: the last-tank routine
The ten-minute routine for the season's last tank — dose, run, top off, park — that decides whether anything starts on the first pull next year.
Read at the bench →Boat tanks, water, and the long sit
A boat tank breathes damp air all season. Why marine fuel needs its own stabilizer, and how one ounce per five gallons keeps the water down.
Read at the bench →Fuel stabilizer, explained from the shed door
Modern pump gasoline is a moving target. Most of it carries up to ten percent ethanol, and ethanol loves water: it pulls moisture straight out of humid air, and when it has absorbed all it can hold, the blend lets go — phase separation — leaving a corrosive water-alcohol layer at the bottom of the tank, exactly where the fuel pickup lives. Add oxidation, which starts turning light fuel compounds into gums and varnish within about thirty days, and the quiet machine in the shed is sitting on a slow chemical problem. A gasoline fuel stabilizer is the counterweight: antioxidants to stop the gumming, corrosion inhibitors to protect the metal, and a water-management package to keep moisture from pooling.
Ethanol Shield approaches it the way an equipment maker would — because that is who tests it. The formula stabilizes fuel for up to three years, carries a vapor corrosion inhibitor that protects above and below the fuel line, conditions rubber and plastic, and adds a top-tier P.E.A. detergent that keeps carburetors and injectors clean while the engine runs. It works in all two-cycle and four-cycle engines and in every gasoline, with or without ethanol. The marine blend doubles the antioxidant package and triples the anticorrosive load for tanks that live over water. Whether the fuel is in a mower, an outboard, a generator or a jerry can on the garage floor, the routine is the same: pour the ounce, run the engine, and the last tank of the season takes care of the first morning of the next.
Put the shield in before you put it away
Grab the twin pack, treat everything that burns gas, and forget about it until the grass grows back.