Best Fuel Stabilizer For Generators

Fuel stabilizers are one of the better semi-secrets among people who really care for their generators (or indeed, their engines, because you can obviously use them in cars and even boats).

They help keep your fuel fresh and viable for much longer than would otherwise be the case – especially when that fuel is gasoline, as opposed to, say, propane.

If you’re going to leave the fuel in your generator over a winter when the RV is resting, you might well want to add some stabilizer to your generator fuel before you close down operations for the season.

Best Fuel Stabilizer For Generators

Alternatively, if you want to make sure that your generator is not, for instance, clogged with particulates and gunk when you use it, you might want to use a fuel stabilizer to clean the system.

That will make sure you’re not losing out on the efficiency of the generator’s operation and the amount of electricity per gallon you can generate with it.

But it’s not quite as easy as grabbing any fuel stabilizer off the shelf of your local RV supply store.

In fact, there are a surprising number and variety of fuel stabilizers on the market, and each one is formulated slightly differently, to deliver different benefits. 

How can you tell which are the best options for your generators?

It’s OK, we’ve got you covered here. We’ve lined up a top 5 for you to choose from - including some that might surprise you.

In a hurry? Here’s our top pick.


Sea Foam SF-16 Motor Treatment - 16 oz. , white

Seriously? Sea Foam? But that’s for boats, right? The clue is kind of in the name, no?

Well, sure – we’re not going to disguise that from you. It’s a product ideally designed as a marine fuel stabilizer, but it’s also capable of a heck of a lot more than that.

If you store your RV or motorhome for some months of the year between trips and travels, you don’t want to lose out on the gasoline attached to your generator.

Sea Foam will keep the gasoline stable, so that the next time you take out the rig, you still have a viable source of generator fuel.

Heck, while you have it, it’s no slouch added to the gasoline in the RV’s actual fuel tank, either.

More than the stabilizing effect while the generator and the RV sit unused though, it’s handy while you’re out on the road to give you a slick, clean, effective stabilizer when you fire up your generator, helping give you an efficient generator experience and all the electric power you know your generator is capable of delivering.

 Sea Foam acts to clean the generator’s system as it’s being used, so if your generator hasn’t had a thorough internal clean for a while, any carbon deposits, any potential scorching are liquified and lubricated, making for a more effective generator while it runs.

If there’s a downside, it’s probably that we’ve gone in at the high end of the pricing spectrum, so you have to believe in the value it’s adding to your generator fuel to willingly pay the price for it.

Also, while it will do both jobs – the cleaning while the engine’s running and the stabilizing of the fuel while in storage, because of the price factor, you can get our best value out of it by taking it along on your trip and using it in active generators rather than resting ones.

Nevertheless, there’s a distinct improvement to the running of generators running on fuel stabilized with Sea Foam, which is why it takes our top spot in this poll.


  • It stabilizes your fuel over an RV break, so you still have viable generator juice when you start back up
  • It cleans and soothes your generator’s motor when you use it, getting to places that are otherwise hard to reach
  • It can even remove carbon deposits laid down by the use of unstabilized gasoline


  • It’s up at the top end of the pricing spectrum for fuel stabilizers, which might encourage you to be overly sparing in using it


STA-BIL Storage Fuel Stabilizer - Keeps Fuel Fresh For Up To Two Years, Effective In All Gasoline Including All Ethanol Blended Fuels, Treats Up To 80 Gallons, 32oz (22214), Red

From one of the costliest fuel stabilizers, our runner up is one of the most budget-friendly.

Better when it comes to stabilizing fuel over protracted breaks than the Sea Foam, Sta-Bil can keep your fuel fresh for anything up to 24 months – which is much, much longer than you should need to keep your generator fuel stabilized.

Certainly it will keep your generator fuel (and come to that, your engine fuel) fresh over the winter break if you decide not to break out the RV over the colder months.

It takes the water from any fuel system, which helps to keep the fuel fresher for longer than many on the market.

If you need a stabilizer more for cleaning the motor while you’re using it, you’re better off going the Sea Foam route, because the Sta-Bil is formulated more for those longer gaps in usage.

But if you know you’re putting the RV away for the season, add some Sta-Bil to your generator fuel before you shut down your systems, to make sure you don’t waste or have to sacrifice your fuel.


  • This stabilizer will keep your fuel stable for up to two years, which is far longer than you should need
  • Sta-Bil is among the most budget-friendly fuel stabilizers you can buy for your generator
  • Sta-Bil has a strong reputation among the RB community


  • This is not your best option for cleaning and smoothing the motor of your generator


STAR BRITE Star Tron Enzyme Fuel Treatment - Concentrated Formula 32 oz - Treats 512 Gallons

There’s something scientifically beautiful about the Star Tron Enzyme Fuel Treatment Concentrate.

As the name suggests, it contains enzyme technology, unlike most other stabilizers on the market. 

What the enzymes do is something similar to the water-removal action of the Sta-Bil stabilizer – they get rid of both the water in the gasoline and the sludge that can accumulate in the system as the fuel is used.

The Star Tron stabilizer also helps prevent phase separation, which also boosts the stabilization action over time if you’re covering up the RV for winter.

When you run your generator, it accumulates small particles in the system that can reduce the efficiency with which it works.

The Star Tron enzymatic stabilizer helps clean out those particles and bring your efficiency back to what it should be, so you get the maximum electrical benefit from running your generator.

Is there a downside to the Star Tron stabilizer? Kind of, sure.

It’s a weird one, though – the design of the Star Tron bottle is cool to look at, but it’s on the tricky side to use when you’re trying to pour the stabilizer into your fuel tank. 

That aesthetic can lead to spilled – which is to say, wasted – fuel stabilizer, and that can translate to dollar bills going up in smoke.

There’s lots to make the Star Tron stabilizer an appealing additive for your generator, but if you’re one of Nature’s klutzes, you might want to transfer it to another receptacle before you try to use it.


  • The enzymatic action of this stabilizer helps reduce the water content of your gasoline – which helps keep it fresh over long winters – and reduces sludge build-up in your generator as it works
  • The Star Tron stabilizer gives you phase separation for effective stabilization over time
  • It helps to get rid of microscopic particles in your generator that can stop you getting the full efficiency out of the machine


  • The bottle is pretty to look at, but can be tricky to use without spilling the stabilizer, leading to wasted money that could be used on other things


Royal Purple Max-Clean Fuel System Cleaner and Stabilizer 11722 20 Ounce

We’re not going to lie to you this far down our list, any more than we did at the top of it.

The Royal Purple Max-Clean Fuel System Cleaner And Stabilizer is essentially calibrated more for car and RV engines than it is for your generator. 

But, as we saw with the Sea Foam, just because a stabilizer is principally aimed at one purpose, it doesn’t mean it has no more tricks up its sleeve.

As formulas go, this is pretty state-of-the-art, doing all the things you’d expect it to – reducing sludge and build-up, cleaning the system during use, and even streamlining your generator’s horsepower, to ensure you get the maximum electrical output from it.

If you find your generator is not giving you all the juice you want and expect, you could do a lot worse than running your next tank of gasoline through it mixed with some Royal Purple stabilizer, then measuring any increase in its efficiency. 

The Royal Purple is more of an active puppy than one that will stabilize your fuel over the winter break, but to make sure you get the most out of your generator when you start up at the beginning of the season, you could do a lot worse than run your first fuel of the season stabilized with the Royal Purple, to clean out any of the kinks in the system. 


  • The Royal Purple stabilizer cleans out gunk and build-up in the system
  • It helps to maintain your generator at its peak efficiency
  • The state-of-the-art formula is made for vehicles, but works well on generators too


  • This is not your first go-to for overwintering


Lucas Oil 10303 Fuel Stabilizer - 1 Quart

We’ve said that the Royal Purple is probably not your go-to for overwintering fuel.

Lucas Oil Fuel Stabilizer can help you with that, and still helps clean out your fuel and your motor system of all the accumulating gunk and particles than can stop your generator from delivering at its peak efficiency.

In fact, if your generator gets a dose of the Lucas Oil stabilizer, your fuel should be fine for much longer than a winter. That’s some impressive performance for a less high-end stabilizer.

If there’s a downside that forces the Lucas Oil stabilizer as far down the list as we find it, it’s an economic issue.

You’ll need a fair amount of the Lucas Oil stabilizer per gallon of gasoline.

Compared to stabilizers like, for instance, the Sta-Bil, it begins to look like the choice of those who are made of money, because you can get a lot more done with the Sta-Bil. 

That doesn’t detract from the quality of the results the Lucas Oil stabilizer will give you though, which is why it still earns a place on our list. It may have poor value for money compared to some other stabilizers on our list, but that doesn’t reflect any poverty of performance of the job at hand. 


  • The Lucas Oil stabilizer will keep your generator fuel viable for anything up to a year between uses
  • It cleans out hunk and particles to help ensure your generator runs at peak efficiency
  • It’s a highly effective fuel additive in both conditions, despite being less well-known than some on our list


  • It represents relatively poor value-for-money compared to some additives on our list, as you need to use quite a lot of it per gallon of fuel to be stabilized

Best Fuel Stabilizer For Generators Buying Guide

When looking for fuel stabilizer specifically for your generator, rather than for your RV’s gas tank itself, there are a handful of things to keep in mind.

Overwintering Performance

Are you looking to stabilize your generator fuel while your RV is overwintering? Normally, as in machines like your lawn mower, if you leave gasoline to stand over that length of time, it will evaporate or turn to useless sludge.

If you’re planning to treat your generator’s gasoline before an overwintering, remember to favor those stabilizers that keep your gasoline viable for longer.

In Operation Performance

If on the other hand, you’re mostly concerned with keeping the performance of your generator at the peak of its potential while it’s in use, there are stabilizers that are formulated more towards this function.

Again, it’s worth checking at least through a list like our own to find out which stabilizers are more effective at which kind of stabilizers are better at delivering which outcome, and choosing a stabilizer that is better at doing the job you need it to do.


It’s worth considering the economics of your choice of stabilizer. Firstly, how much of the stabilizer do you need to achieve the desired result with your generator’s fuel.

And just as importantly, could you use more of the same stabilizer to keep the fuel in the RV’s tank viable over a winter, or running smoothly during a road trip?

Are there economies of scale you can take advantage of, or are you likely to end up buying more than one kind of stabilizer to equip both the vehicle itself and the generator inside it? 

Frequently Asked Questions

Should I Use Fuel Stabilizer For My Generator Fuel?

It’s a free country, and fuel stabilizer is a purely optional extra. The question is really whether you intend to leave fuel in the tank of your generator over a long period – in which case it might well be sludge by the time you come back unless you use a stabilizer.

Alternatively, have you noticed your generator performing at significantly less than the level you expect of it?

If the answer to either of these questions is yes, then running some stabilizer through your generator fuel is by no means a bad idea. It will help keep your fuel viable over a winter, and could well tune up the performance of your generator, so you get peak performance from it again.

Can Fuel Stabilizer Revert Old Gasoline So It’s Usable Again?

No. Sadly, that would be outside the remit of stabilizer and more in the realms of alchemy.

The point of fuel stabilizer is that you add it to good, fresh fuel to stop it from becoming old and unusable. Once it’s made that journey into gunk, there’s no bringing it back.

How Long Does Fuel Stabilizer Stay Viable?

Tricky. There’s no precise answer to this, and the answer that doesn’t exist changes depending on the formulation and whether or not it’s in use. Some stabilizers keep fuel viable for as long as two years while they’re in use, but may not stay viable themselves on the shelf for that long.

Ideally, keep your fuel stabilizer in a sealed container until you’re ready to use it, so as to maintain its viability as long as possible.

Is There Such A Thing As Too Much Fuel Stabilizer?

Well, yes. Chemistry is a fickle mistress, and too much stabilizer in your fuel will – perversely enough – make the mixture unbalanced. That’s why most fuel stabilizers will come with fairly precise instructions on how to use them, and how much to add per gallon of gasoline.

They are distinctly instructions, not suggestions. The last thing you want to do is adversely affect the mixture and effectiveness of your fuel and your stabilizer. That’s entirely counter-productive to adding stabilizer to your fuel in the first place.

I'm an environment and energy blogger who teaches outdoor and energy enthusiasts how to be better informed when it comes to purchasing or maintaining a generator, solar panel system, or anything else related to your energy needs.