Fuel Additives for Gasoline Lawn Mowers - Do It Yourself Outdoors (2023)

New 2022 edition! We've made a few changes to our recommendations to give you the best possible experience and get your mower up and running again.

Whether you're servicing a small backyard or an entire neighborhood, making sure your equipment is performing as intended is vital. These gasoline additives will help keep your lawn mower engine clean, free of gasoline gum and varnish, and protect it from corrosion from low-grade gasoline and ethanol. These are our favorite mowers and our expert opinion on which ones are the best.

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  1. What are fuel additives?
  2. Does the gas no longer contain additives?
    • Ethanol
  3. Fuel Additives for Lawn Mowers
    • Treatment of small engines STA-BIL Fast Fix
    • Chevron Techron Concentrate Plus
    • Meerschaum Engine Treatment
    • ox fuel
    • wonder mystery oil
    • GumOut Multi-System Tuning
    • STA-BIL Original
    • STA-BIL 360 Protection
    • Complete PRI-G gasoline treatment
    • Archoil AR6200
    • STP Ultra 5-in-1 Plus Fuel Cleaner and Stabilizer System
    • Star Tron Fuel Treatment
    • Lucas Ethanol Fuel Conditioner with Stabilizers
(Video) How to Winterize your Lawn Mower with Fuel Stabilizer

What are fuel additives?

Fuel additives are chemicals designed to mix and blend with fuel, improving the properties of the fuel. Without getting too technical, here is an overview of the common types of fuel additives:

  • solvents, designed to clean carburettor jets, fuel pumps and injectors of deposits and sticky residue.
  • detergents, to help reduce carbon and scale in valves and combustion chambers.
  • combustion intensifiers, which allow the fuel to vaporize more easily and therefore burn more completely.
  • Antioxidants, which help keep fuel cold for long periods of time and help prevent corrosion.
  • Top Cylinder Lubricants, which help combat ring and cylinder wear.
  • Decarbonizing agents, specifically for dissolving hard carbon deposits in valves and cylinders.
  • water removers, to help the water better dissolve into the gas so it doesn't build up in the tank.

Some additives such as Polyetheramine (PEA) perform several of these tasks at the same time. Fuel additive manufacturers perform extensive testing to ensure their blend is compatible with commonly found fuel types.

Does the gas no longer contain additives?

The federal government requires a minimum of detergent additives in gasoline to help reduce pollution and optimize efficiency. However, these detergents cost money, and more detergent means more expensive fuel. With today's already expensive fuel prices, this is a benefit few would spend more for. some kinds ofpremium fuel brandsThey are marketed with much more detergent than federal standards, but these detergents do little to help stabilize fuel for long-term storage or remove water that has entered the fuel system. Combine this with the poor storage attributes of ethanol fuels, as well as the tendency to pull water out of the air, and the basic gas pump is no longer enough.

Edit: Starting in 2022, an enduring supply crisis and our new global dynamics mean that even the best fuel brands may not be adding as many additives as before. Fuel quality is low in all sectors: everyone manages to survive, even big companies!Find an off-the-shelf product and add it to your fuel, seriously.

(Video) Does Fuel Deteriorate Faster Outside? Let's See


The ethanol in the fuel is a mixed blessing. It is much safer than MTBE, which was used in the past, but it tends to absorb moisture from the air. This moisture can cause rust, oxidation and, in some cases, bacterial growth in fuel tanks. Ethanol-based fuels have been known to age much faster than non-ethanol blends in the past. Without an additional stabilizer, some ethanol blends have been known to go bad in less than three months. This doesn't matter for an everyday car, but for a small engine that is rarely used it can be a disaster.

The best gasoline for lawn mowers is one that does not contain ethanol, but in some places it cannot be bought or is too expensive.

Fuel Additives for Lawn Mowers

Many fuel additives are multi-functional and useful in any engine, whether it be a snow blower, lawn mower, pressure washer, or other device. But the summer weather that many people associate with mowing has different needs than the cold winter months. In order of importance, we evaluate the effectiveness of additives in this order.

  • stabilize fuel
  • Reduce and/or prevent damage or corrosion caused by ethanol
  • Reduce and/or eliminate carbon and varnish from the fuel system
  • Upper cylinder lubrication or combustion enhancement to improve efficiency
  • water removal

In the hot summer months, stabilizing the fuel and preventing ethanol problems will provide the greatest increase in reliability, followed by ease of cleaning and increased fuel efficiency. Water removal is at the bottom, as fresh gas tends to be readily available. If you have problems with water, check the fuel supply and use aseparatory funnelit can often solve many of these problems. So if you're ready for less hard starting, rough idling, malfunctioning equipment, and you're ready to explore solutions, read on and check out our recommendations below.

Treatment of small engines STA-BIL Fast Fix

STA-BIL Fast Fix is ​​a new option on the market, designed specifically for use in small engines. Cleans carburetors and injectors, repairs malfunctioning engines, and removes water from fuel - all major headaches for small engine owners. It is designed to be "one and go" so you can get back to work if you have fuel problems. The formula is made for 2-stroke and 4-stroke engines and can be used in lawn mowers, chainsaws, pressure washers, generators, and other similar small engines. Fast Fix also claims to be able to remove carbon deposits, adding value. The only thing we didn't like is that the product is not a long-term fuel stabilizer; We think it's a great option to get you back up and running, but you're better off going with the "360 Protection" product if you want something that will also keep your fuel cool.

Chevron Techron Concentrate Plus

Chevron Techron is the best-selling product, aimed primarily at the automotive market. It is one of the first fuel system cleaners to contain PEA, a new type of fuel detergent that works better in modern engines. However, Techron does not claim to be able to stabilize fuel for poorly running engines that just need a good cleaning; this can be a great choice. With a treat rate of just 1 oz. per gallon of fuel, you get enough for 32 gallons of gasoline.

(Video) Why DON'T Fuel Additives Work?

sea ​​foam motor treatment

Is your mower a SeaFoam mower? SeaFoam has quickly become the gold standard of fuel additives, originally created to help marine outboards perform better. It is popular not only in automotive circles, but also among small engine users; why thatit works🇧🇷 SeaFoam claims to be able to clean carburetor jets, reduce moisture in fuel, stabilize fuel for up to 2 years, remove deposits, and lubricate the fuel system. Many of the users we spoke to won't use anything else, because Seafoam does everything so well. Or as veterans would say: “Rough Idle? Just add sea foam.”

ox fuel

Fuel Ox is a really cool product that contains a combustion catalyst, much like Archoil. They claim it will lower the flash point of the fuel, which means an increase in power and efficiency of up to 10% and a 60% reduction in emissions. Fuel Ox is fully compatible with all common fuels, including gasoline and diesel. In addition to improving performance, the fuel ox removes water from gas, protects against ethanol corrosion, lubricates top cylinders, and stabilizes fuel. This makes Fuel Ox a solid contender on our list.

We really like the fact that Fuel Ox reduces emissions, while we like to keep our equipment running smoothly, making sure the fuel burns better means more fuel is spent on the job and less is thrown into the sky. Good for your wallet, good for the environment, everyone wins.

wonder mystery oil

Marvel Mystery Oil has been around since 1928, and its wintergreen-scented red bottles have graced many a garage. While it doesn't contain advanced technology like some of the other additives we've mentioned, it's still a great base fuel additive for carbureted engines. The formula can also be used in oil to help clean and remove drool. The cost is generally low, and with a treatment rate of only 2 ounces per 5 gallons of fuel, it also tends to be inexpensive for constant use.

Many of our experts have noted lower fuel consumption, as well as an elimination of carbon and spark plug fouling with the use of Marvel. It won't be able to remove water from the fuel tank, but it's still a solid all-rounder for general use. Veterans also like to use it as a household oil and in their air tools, something we have started to do as well.

GumOut Multi-System Tuning

GumOut sells a full line of fuel additives and fuel system cleaners, but their Multi-System Tune-Up product has become a favorite. Multi-System Tune-Up contains PEA, a new technology type of detergent that is specifically optimized to clean better than traditional solvents alone. Otherwise, it's like SeaFoam in versatility. GumOut stabilizes fuel, cleans the fuel system, reduces harmful deposits and fights fuel system corrosion.

(Video) Proper Way To Tip A Lawn Mower Over

STA-BIL Original

Sta-Bil has been around for a long time, and for many, this was the first fuel additive they heard of. Primarily a fuel stabilizer, it also helps remove water, prevent corrosion, and keep the fuel system clean. Stabil claims to be able to stabilize fuel for up to 2 years. We found that while it's a good product, it doesn't seem to be as effective with ethanol. Use it if you have it, but we recommend using 360 products instead if you can find it.

STA-BIL 360 Protection

Sta-Bil 360 is like the original Sta-Bil, being primarily a fuel stabilizer. Unlike the original, however, this product was specifically designed to provide protection against ethanol, at the cost of stabilizing the fuel for only 12 months instead of 2 years. Sta-Bil 360 also helps reduce harmful gums and varnish in the fuel system to keep your equipment's carburetor or injectors clean. If you want a fuel stabilizer for your lawn mower and other small equipment, but also want extra cleanliness and protection, 360 Protection is a great all-round option.

Complete PRI-G gasoline treatment

The G in PRI-G stands for "Gasoline." Described by some as "Stabil on steroids," PRI Research claims that PRI-G can restore even bad, old fuel to usable condition. This means that PRI-G may be the best fuel treatment for bad gases. PRI-G vs Stabil became the new "which truck is better?" among some we know, and we know that we should not get into this fight. PRI-G makes the usual claims, like other additives, about improving combustion efficiency and fuel system cleanliness. What we know: Regular PRI-G users swear by the product, and the online reviews speak volumes. If you need a fuel additive for old gasoline, here it is!

Archoil AR6200

ArchOil is a newer product and very popular among diesel engine users. However, Archoil AR6200 can also be used with gas. This product is primarily a combustion enhancer, with up to a 5% improvement in overall MPG. On fuel injected machines this can reduce the fuel required, but we have found that on traditional carburettor kits it seems to have little effect. Archoil AR 6200 also contains a fuel stabilizer and a certain amount of detergent to help remove varnish from the fuel system and keep the engine clean.

Updated for 2022:This product has become hard to find. If you liked this product,ox fuel, also reviewed on this page, is similar in many ways to the Archoil fuel treatment.

STP Ultra 5-in-1 Plus Fuel Cleaner and Stabilizer System

STP Ultra 5-in-1 Plus seems to be the best "general purpose" additive we have tested. STP claims that the 5-in-1 plus contains 3 times the amount of detergent as regular gasoline, as well as containing a hefty dose of fuel stabilizer and ethanol fighting power. We tested this not only on our lawn mowers, but also on snowplows and cars; and it works equally well in all applications. Like Gumout and Seafoam, STP Ultra 5 in 1 Plus is a multi-purpose additive that can be used in both oil and fuel. This is our current favorite of the bunch and we think you'll like it too.

(Video) “testing" to see if gasoline is GOOD or BAD

Star Tron Fuel Treatment

Star Tron fuel treatment uses enzyme technology to prevent ethanol-related gas oxidation, as well as stabilize fuel and help keep engines clean. The manufacturer makes strong claims about rejuvenating old gasoline and "curing ethanol problems," specifically with regard to small engines. The treatment fee is EXTREMELY inexpensive, with a 16 oz bottle capable of stabilizing 256 gallons of gas. We're not sure about these claims, but for the value-conscious consumer, this might be the one. Star Tron also helps keep engines clean and helps reduce and/or eliminate gum and varnish in the fuel system. This is our value pick due to the very cheap handling fee. A little seems to go a long way with these things, and the high reviews seem to back it up.

Lucas Ethanol Fuel Conditioner with Stabilizers

A fresh take on an earlier product, Lucas Fuel Treatment has been around for a long time and is popular in the trucking and racing communities. Lucas Ethanol Fuel Conditioner was specifically developed to help solve fuel problems due to ethanol use, i.e. fuel system corrosion. The product is compatible with any type of gasoline, including E-10, E-15 and E-85. In addition to preventing corrosion, Lucas contains inhibitors to help stabilize fuel over time and additives to help clean injectors, valve seats, combustion chambers and other critical parts. If you like Lucas brand products and know them well, we think this one will be a solid performer as well.


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