The Best Fuel Stabilizers for Outdoor Power Tools

Long winter storage and infrequent use can wreak havoc inside gas-powered equipment. These superior stabilizers can keep your tanks fresh and your fuel systems running smoothly.

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The Best Fuel Stabilizer Option

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When the time comes to store your prized tractor, motorboat, or other fuel-powered gear for the winter, you don’t want to worry about gasoline or diesel “going stale,” gaskets and seals dry-rotting, or gunk building up in your fuel lines. Most of those situations can be a nuisance when you bust out your equipment again next year—an expensive nuisance at that, if it means a trip to a small engine shop for repair.

Adding a fuel stabilizer to your tank can circumvent these problems. It’ll keep gas fresh and gunk free, and also help retain the fuel’s ignition vapors, necessary for easy starting—let those vapors dissipate and you’ll be yanking the pull-start in frustration, guaranteed. Pour one of the best fuel stabilizers directly into the tank of your ride-on mower or tractor, or a fuel jug that you store for your snowblower.

Though fuel stabilizer formulas can be a bit complicated, mixing needn’t be a challenge. Most manufacturer directions will call for 1 ounce of stabilizer per a certain number of gallons of gas—the stabilizer-to-fuel ratio. A 1:10 ratio, for example, calls for 1 ounce of stabilizer for 10 gallons of gas, while a 2:5 ratio means 2 ounces of stabilizer for every 5 gallons of gas. It’s that simple—so take good care of your gas-powered gear with some of the best fuel stabilizers reviewed here, chosen for performance, price, brand, and overall customer satisfaction.

Our Top Picks

Below, you’ll find some of the best fuel stabilizers for most situations, whether you’re stowing your fishing boat’s motor or putting your classic tractor away for the winter.

The Best Fuel Stabilizer Option: STA-BIL 22207 Fuel Stabilizer - 16 oz.

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1. BEST OVERALL: STA-BIL 22207 Fuel Stabilizer – 16 oz.

If you want a fuel stabilizer with a tried-and-true reputation, look no further than the STA-BIL Storage Fuel Stabilizer. It works for all gasoline engines, including power equipment, recreational vehicles, and generators, with a unique formula that provides optimal results while storing. STA-BIL will preserve gas quality, making starting after storage as painless as possible, and it protects fuel for up to 24 months. It does require a somewhat highly concentrated stabilizer-to-fuel ratio, but it’s worth it for the end result of perfectly usable gas with very little ethanol-caused fuel system damage.

The Best Fuel Stabilizer Option: Lucas Oil 10314 Fuel Stabilizer - 8 oz.

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2. RUNNER-UP: Lucas Oil 10314 Fuel Stabilizer – 8 oz.

Gearheads and motorsports fans are familiar with Lucas Oil products, as the company has a sponsored vehicle in nearly every race. They make high-performance products, and this fuel stabilizer is part of the lineup. It works for all gasoline fuel systems, including two- and four-stroke engines. It prevents fuel degradation and the harmful effects of ethanol on a fuel system like rust and corrosion, and this versatile product also cleans and lubricates fuel pumps, carburetors, and injectors. It requires a relatively high concentration, however, at 1 ounce to 1 gallon of fuel, which makes it slightly more expensive to use than our best overall pick.

The Best Fuel Stabilizer Option: Star Tron Enzyme Fuel Treatment Concentrate

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3. BEST BANG FOR THE BUCK: Star Tron Enzyme Fuel Treatment Concentrate

If you aim to stretch a fuel-stabilizing buck, reach for Star Tron’s Enzyme Fuel Treatment Concentrate. This formula is highly concentrated, so one bottle will treat 256 gallons of gas (the breakdown is 1 ounce per 16 gallons). It stabilizes and maintains gasoline performance for up to two years in all engines, including two-stroke engines like chainsaws and some ATVs. It’s perfect for anyone with lots of toys and equipment, as one bottle really does go far, but Star Tron recommends an initial dosage of twice the strength. After the initial dosing, you can drop down to the standard ratio.

The Best Fuel Stabilizer Option: Royal Purple Max-Clean Fuel Cleaner and Stabilizer

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4. UPGRADE PICK: Royal Purple Max-Clean Fuel Cleaner and Stabilizer 

If you’re using a side-by-side or ATV to maintain your property—and especially if you plow snow with your machine—you know how important it is to keep good, clean fuel in the tank. Royal Purple’s Max-Clean Fuel System Cleaner and Stabilizer is the perfect addition to a performance-oriented engine, minimizing the effects of stale gas and ethanol damage. Use it and you’ll get quick starts, plus the high performance necessary for moving heavy loads like snow and yard debris. The Royal Purple formula works in both a 4-cycle side-by-side and a 2-stroke ATV, and both gasoline and diesel fuel systems, so you won’t need to buy multiple stabilizers. One ounce per gallon will treat a fuel system, and Royal Purple suggests annual use, so you can expect it to stabilize fuel for 12 months.

The Best Fuel Stabilizer Option: Briggs & Stratton 100117 Fuel Treatment & Stabilizer

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5. BEST FOR YARD EQUIPMENT: Briggs & Stratton 100117 Fuel Treatment & Stabilizer

Briggs & Stratton knows a thing or two about small engines—they’ve been building them for over 100 years. That’s why the company’s Advanced Formula Fuel Treatment and Stabilizer works so well for yard equipment. This 4-ounce bottle treats up to 20 gallons of gasoline and helps preserve the fuel’s quality for easier starts and better performance. Briggs & Stratton Fuel Treatment and Stabilizer protects for up to three years, which makes it an excellent choice for rarely used power equipment like post-hole diggers or tillers. Also, for folks with vacation homes or second residences, long treatment windows can mean the difference between maintaining a mower or buying a new one every other year.

The Best Fuel Stabilizer Option: STA-BIL (22240) 360 Marine Ethanol Treatment

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6. BEST FOR SMALL BOAT ENGINE: STA-BIL (22240) 360 Marine Ethanol Treatment

Moisture can destroy a fuel system—so a boat’s fuel system is particularly susceptible to rust and corrosion. STA-BIL’s 360 Marine Ethanol and Fuel Stabilizer treats the entire system with a protective coating, minimizing the negative effects of water and ethanol, and has water removing properties to keep fuel pure. This formula will keep fuel fresh for up to 12 months and you’re likely to get better fuel mileage with STA-BIL in the tank—a real benefit considering how pricey gas is at marinas. One ounce of STA-BIL 360 Marine is enough to treat 10 gallons of gasoline, and although it’s specially formulated for boats, you can use it in all of your gasoline tanks and jugs.

The Best Fuel Stabilizer Option: STA-BIL (22254) Diesel Fuel Stabilizer

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7. BEST FOR DIESEL ENGINES: STA-BIL (22254) Diesel Fuel Stabilizer

If you ride a classic diesel tractor for yard maintenance, it’s probably your pride and joy. And you’re no doubt acutely aware of what cold weather can do to diesel fuel. Adding STA-BIL Diesel Fuel Stabilizer to your fuel tank will help avoid the gel, sludge, and sediment buildups that cause clogged fuel filters and hard starts. This stabilizer follows the STA-BIL 1:10 ratio of ounces of stabilizer to gallons, so this bottle will treat several pieces of equipment, including diesel generators or vehicles. Be aware, however, that this product is for diesel engines only; don’t use it in a gasoline fuel system, where it’s bound to cause poor performance or damage.

The Best Fuel Stabilizer Option: STA-BIL (22295 360 Protection Ethanol Treatment

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8. BEST FOR GAS JUGS: STA-BIL (22295 360 Protection Ethanol Treatment

Most folks store gasoline for their power equipment in 2.5- and 5-gallon fuel jugs, and measuring a quarter of an ounce for a 1:10 ratio is a pain. Since no one wants to spend time measuring smelly, fuel-based chemicals, STA-BIL’s 360 Protection comes in a 4-ounce bottle that will treat 5 gallons of gasoline, making it ideal for gas jugs and small tanks. For smaller fuel jugs, simply dump in half of the bottle; larger jugs will take the entire bottle. While this formula helps to reduce the harmful effects of ethanol on a system (such as rust and corrosion), the primary use in a fuel jug is to preserve the quality of the gasoline. This fuel stabilizer helps remove moisture from the gasoline and maintain starting vapors so you can just top off your equipment in the spring and get going.