Fuel stabilizers

Joined
Jul 27, 2012
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771
Location
Perth, Western Australia
Ok, so i have bugger all expectation of actually getting anything useful from this thread, but occasionally I'm surprised so here goes.

Fuel stabilizers. After weeks of reading I get the impression they try and prevent fuel degradation by retarding oxidation and evaporation. I can see how that might work, and enough people use them I suspect in some way, shape or form they actually do something.

In our gear (mowers and generators mainly) we use non-ethanol fuel, and generally drain both the carb and the tank before we put them away. The remaining fuel goes back into a sealed container, and in "general" it doesn't hang around for more than 12 months because we don't keep much more than a US Gallon handy and get through it in less than a year. The Generator however might be stored for 18 months before it's pulled out again.

If I were to logically preserve an empty fuel system, I'd probably coat the inside from the tank to the carb in an oil of some kind while it was empty. Pretty much every fuel stabilizer says it protects the inside of the fuel system against corrosion. I suppose the question is do they leave any usable protective film behind or do they only protect the system if it's actually full of fuel?

I blow the generator fuel system clear with low pressure compressed air for storage. I could easily flush a bit of 2 stroke oil through it before I put it away. Would something like Sta-Bil in the fuel leave any protective film once the system has been emptied?

Frankly most of it reads as snake oil, so I'm a bit perplexed.
 
I've given up on pump fuel being any good. While I still use Stabil in my non ethanol fuel for the tractor it is mostly out of habit and the fuel may or may not sit. Recently found a jug that was two years old that I put 90 octane non E gas + SB in. It smelled ehh. Not fresh, not stale. But on it's way to going bad. Used it up right away and seemed to run fine.

Long ago I switched to VP racing fuels 'C9'. It is a 96 octane storage and race fuel. I have never had the fuel go bad, nor does it result in dried out needle and seats, leaking fuel petcocks or deposits and other storage related problems when put away dry. Plus the stuff runs very crisply in all my tools and toys.

My point is that storage fuel has been the ideal solution for me. It simply works.

My Polaris 330 Trail-Boss ATV sat for years with C9 in it. So much so, it was covered in mildew. Put in a new battery, cranked right up and runs strong. Fuel smells fresh.
 
Just another note, 100LL Avgas is a great long life fuel. It does tend to dry out seals, so it may not be ideal for dirt bike storage. But it will last 10 years or more in a sealed can.

Clearly, a quality fuel like VP C9, certain race fuels and Avgas is designed not to degrade, unlike pump fuels. Taking generic pump fuel and introducing a stabilizing additive has never really worked for me.

Keep in mind I'm in South Florida where it is hot and humid much of the year. So fuel in the shed goes bad quickly.
 
Long ago I switched to VP racing fuels 'C9'.

WOW! I just looked it up in Australia because it's available here in 19L and 200L containers. Let me do the conversion...

$30.01 USD per US Gallon. I currently pay $4.19 USD per US gallon for RON 98. I can evaporate awful lot of old fuel for the price difference!
 
The longer I fiddle with this stuff and broken promises from Sta-bil, the more I like the idea of just running 40:1 two-stroke oil for the last pint of fuel for a device for the season. I want oil coating my stuff, it's better than "green crystals" that form from E10. I'm currently doing a study to see if it's any better this way.
 
I've stopped draining carbs, and just use treated E0 fuel year round. I've had more issues with starting from a carb sitting empty, and I've had no issues with starting in the spring with treated E0 fuel sitting in the tank all winter. I run the tank down to about a 1/4 and let it sit. Fill it up with fresh fuel in the spring, and let it rip. Never an issue. Every gas can gets a fill of 91E0, stabil, and a tiny dose of Regane.
 
I don't expect miracles, I use good dry non-ethanol in my OPE and petrol gennie with Amsoil fuel stabilizer. Ask me if I expect years - NO. But a year storage of fuel should not be an unreasonable ask. Some of this depends where stored. The equipment in the shed gets better treatment than the generator in the temperature moderated garage.

Keeping some lube on uncoated metal in the fuel system is smart, and there are even some spray storage products, but really a dab of a non-racing 2 stroke OPE oil in the fuel with included anti-oxidizer additives, is better than nothing IMHO.
 
I've had much better luck with Amsoil fuel stabilizer than with Sta-Bil. Pablo should be pleased. Some years ago the Amsoil kept a 1–gal (US, = 3.8 liters) jug of gasoline good enough to use two years later. The container was sealed (of course) in a protected area on a porch out of sunlight. But is the Amsoil stabilizer available in Oz?

You could also check marine supply shops. The boating guys have other brands of stabilizer available because they store boats for the winter, though I'm not familiar with those brands.
 
a bit of 2 stroke oil through it before I put it away.
This⬆️

I now add a capful or so of TWC-3 oil to my seasonal equipment and top off with REC90, and it seems to work. Originally, I used fuel stabilizer for many years but recently noticed rust in the gas tank of my bike. Most likely though, I surmise that the storage term was too long for the stabilizer to handle.
 
I have had very good results with Sta Bil Marine 360 on the toy cars that hibernate. We do not have the option here of easily available non ethanol auto fuel. That said, I have also had very good results on a mix of 100LL and UL aviation fuel on an old inboard boat.

See this recent thread w/ my experience w/ the Sta Bil: Classic Car e10
 
I could easily flush a bit of 2 stroke oil through it before I put it away.
I use Stabil and 1 oz of 2-cycle TCW-3 oil in a 5 gallon jug to fuel all my small engines, year round. I have stored engines over the winter with empty carb, but full tanks. Long term storage I drain carb and tank.

When you drain the carb and tank, the oil will leave a protective film on the insides.
 
When you drain the carb and tank, the oil will leave a protective film on the insides.
This is what I was hoping for more than anything. The Generator might come of 6 times a year, or may stay in storage for 2 years. I just want to fuel it up and go. I don't leave fuel in it. I replaced all the fuel lines with J30R7 a few years ago because after 9 years each and every line (and the primer bulb) had split. Now I empty the tank and blow it all through with compressed air before I store it, but the thought of leaving an oily film in parts like the fuel cock, pump, primer and carby has a certain attraction.

But is the Amsoil stabilizer available in Oz?
Turns out you can order it in, so yes.

Between the mowers, gen & line trimmer we get through a bit of fuel over Summer. I usually buy BP Premium (98RON) for the portable equipment but only 5L at a time. It's well sealed and doesn't seem to go off in the can. I suppose the worst thing that can happen by adding 2 stroke is a bit of plug fouling and some exhaust smoke.

My experience over the years is the more expensive petrol does seem to keep better. After having clogged carbs on one of the mowers, and the Generator I'm just looking at a belt to go with the "drain after use" braces, and something that might help out when Mr 10 year old mows the lawn and forgets to turn the fuel tap off.

I might have to try some TCW3, do a run and empty on the Generator then pull the float bowl to check for any sign of a film.
I've added the Amsoil stabiliser to my next shopping list.
 
I might have to try some TCW3, do a run and empty on the Generator then pull the float bowl to check for any sign of a film.
I've added the Amsoil stabiliser to my next shopping list.
If you want more of a film, you can add more oil to the mix. Some people will run a bit of 50:1 mix through before draining and storage.
I learned about this from guys with vintage motorcycles. That's what they use to store them.
 
I have used Stabil for many years without any problems. I use it in my snowblower, boat, Corvette, push and riding mower and power washer. It seems to work great and I don't keep anything without being started for over a year.
 
If you want more of a film, you can add more oil to the mix. Some people will run a bit of 50:1 mix through before draining and storage.
I learned about this from guys with vintage motorcycles. That's what they use to store them.
I had this thought tonight. The Generator is sitting there drained, blown clear and ready to put away. It'd take me no more than 10 minutes to pour some 50:1 in there, run it for a few minutes and drain the rest back into the bottle. I keep a bottle of 50:1 hanging about for the Sthil line trimmer, so it wouldn't be really onerous.

Given I don't leave things really fueled up and the fuel lives in a sealed container for less than a year, perhaps stabiliser isn't actually warranted. I might try a bit of 2 stroke oil with a stronger dose just prior to storage.

I recently changed to Amsoil Saber 2 stroke oil for all my 2 stroke gear, which seems considerably more tenacious than the Penrite oil I was using before. Let's see how that goes.
 
My OPE gets fuel from a non EPA sealed fuel jug. I use 0E fuel treated with Seafoam and TCW-3. This summer I had to haul out, and run, my generator for 2.5 days on gas that was sitting in it for 8 years. Started in 3 pulls, which is usual, and ran great.
 
WOW! I just looked it up in Australia because it's available here in 19L and 200L containers. Let me do the conversion...

$30.01 USD per US Gallon. I currently pay $4.19 USD per US gallon for RON 98. I can evaporate awful lot of old fuel for the price difference!
VP is not the only game in town though. Sunoco makes the "optima" 95 octane fuel. Also, many race fuels without ethanol are long shelf life fuels.

But yes, that is a silly amount of money. The VP racing store is nearby and I don't purchase the pails, I get it right from the gas pump. Maybe $10/gal now? Worth every penny.
 
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