How long does gasoline last?

I recently discovered that I actually (maybe) do have one appreciating asset. Namely, 30 gallons of 89 octane treated with Stabil Marine 360. The downside: this has been stored in 5 gallon plastic cans since Ida in August 26, 2021.

I figured the gearheads on Power Systems might have some thoughts - is this gas still usable? Stabil says it's good for a year, but ....

Appreciate your observations. Would you put it in your boat's tank?

The key factor is whether or not it has ethanol in it. If it does then I won’t use it. If it doesn’t then it should be fine. We have what is know as Rec Gas here. It doesn’t have ethanol in it. I have used 4 year old Rec Gas that has been stabilized without any problems. Ethanol gas over 3 months or so is questionable.

A lot depends on what you plan to do with it. I wouldn’t put it in a HP engine but I certainly wouldn’t hesitate to run a crusader 454 with it.

If the cans are well sealed and not openly vented, I'd assume it's probably down a little octane by now, but it should otherwise be fine. I've burned year old stabilized gas many times, with and without ethanol.

What I would do is buy an extra 5 gallon jug and slowly pour 4 1/2 gallons into the new jug. The last bit pour into a clear glass or plastic pitcher from the dollar store to look for water. If you have water try to get the lighter gas back into the new jug without transferring any water. The water can be dumped into a bucket. At this point the gas without water is low octane gas that can be mixed with fresh fuel and used. Repeat with each jug.

Neglected to say it was non-ethanol gas. Appreciate the thoughts and experience.

I get a pretty good kick out of conversations regarding when to and when not to use aged gasoline.

Being a decades long masonry concrete and tile contractor; you can imagine how many different types of gasoline equipment, trucks and cars I've gone through and/or still own. Add to that list many, many years of gasoline boats [inboards and outboards]... as well as a motorhome.

My 10 cents: Smell it, try it... you might like it!

Suffice it to say: I have never had trouble caused by old gasoline. Will admit that because ethanol is now often blended in I do use Soltron in tanks that will hold gasoline without use or replenishment for a year or more.

Happy Gas-Use Daze! - Art

Art said:

My 10 cents: Smell it, try it... you might like it!

Suffice it to say: I have never had trouble caused by old gasoline. Will admit that because ethanol is now often blended in I do use Soltron in tanks that will hold gasoline without use or replenishment for a year or more.

Happy Gas-Use Daze! - Art

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Gasoline sniffing led to a special blend,addictive component removed, for our remote areas.
Yours is treated, it should be ok. May depend what you put it in. Our Mercury 3.3 2 stroke o/b, lightness and power output for size, won`t run on older fuel, though adding snake oil seems to help. I bring it home, the 2 stroke garden devices love it.

Not having alcohol in it it will be fine, but will have lost octane a bit. So, best used by adding it to your petrol fuelled vehicle in amounts of about 5 gals per tankful of other fresh fuel, (ie ~ 1/3 to 1/2 a full tank), making the fresh fuel as high octane as possible, especially if a turbo engine. Couldn't go wrong then.

Yes, no ethanol it will be good for years. I would add some stabilizers just to be sure.

He put stabiliser in when he bought it. That should suffice.

I've been burning year old gas in my dinghy outboard all year. In another month or so I'll have burned it all then add stabilizer to a full tank and go at it again next year.

But, the bigger question - should I use year old stabilizer or buy anew?

BruceK said:

Gasoline sniffing led to a special blend,addictive component removed, for our remote areas.
Yours is treated, it should be ok. May depend what you put it in. Our Mercury 3.3 2 stroke o/b, lightness and power output for size, won`t run on older fuel, though adding snake oil seems to help. I bring it home, the 2 stroke garden devices love it.

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Sniffing and smelling are two different worlds.

Smelling [a tiny whiff] goes no further than the olfactory nerves in nose for sensing condition of or trying to answer/recognize the what-is-it?? question. If smelling that an odor is offence or not good to inhale then immediate and repeated exhalation can be accomplished. Breath through mouth exhale through nose - and - repeat as necessary - LOL!

Sniffing each other's BS premises - Is what politicians do when they concoct BS bills that do not take the good-of-the-people into account.

Kidding aside! I learned in grammar school's 6th grade that my casemates who sniffed fumes off airplane glue quickly became stupid in class. Early 1960's that was thought a good way to get high by kids in NY.

Then there's always the case of an idiot in our school who realized he could get high by sniffing gasoline fumes. He soon became a blithering idiot... really, a dumb person that became much dumber!!!

I had almost 1 year old rec gas in my boat in Florida. It ran fine in the 90 hp Merc Optimax.
I did treat it with “Stabil” before it sat.

Year old gasoline will be fine as long as storage temperatures are not hot. Gasoline will degrade with time but that is over a longer period. If the can is sealed there should be no loss of octane since there's nowhere for the lighter ends to go. When I worked in fuels early in my career we used to store fuel samples for a year to test stability without problems. However, I would not leave it for another year.

7 years ago I got a ski boat that had to be substantially refinished. Took it on as a winter project for grandson and me.

One item was remove gas tank for transom restructuring. Tank had about 15 gallons old gas in it. I sniffed its aroma and felt it was probably OK, color seemed a bit dark. Boat had not been used for at least 5 years. I poured it into four 5 gal plastic containers. Then poured it into one of my construction trucks. Probably had about 3 gals of recently new gas already in the truck's tank. High performance 350 cid, 325 hp Chevy engine with Rochester Quadrajet carburetor had no problem burning that gas.

I have no idea if the old gas was an ethanol mix or not.

I've experienced no problem with new or old gas.

I know a guy who accidentally filled his GAS tank with diesel. He was running a 2010 Suzuki 90hp fuel injected outboard. He ran from Port Townsend to Seattle. He called the next day and said his engine performance had fallen off and now his engine wouldn’t start. Thought he got bad gas at port Townsend. One look at his clear fuel filter told me he filled up with diesel. If that engine can run on diesel, 7 year old gas is not going to bother it.

tiltrider1 said:

I know a guy who accidentally filled his GAS tank with diesel. He was running a 2010 Suzuki 90hp fuel injected outboard. He ran from Port Townsend to Seattle. He called the next day and said his engine performance had fallen off and now his engine wouldn’t start. Thought he got bad gas at port Townsend. One look at his clear fuel filter told me he filled up with diesel. If that engine can run on diesel, 7 year old gas is not going to bother it.

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That's a good one!

Art - you mentioned Soltron - you prefer that over Stabil?

tilt - yep, good ole Crusader 454s.

Thank you all - maybe I do have an appreciating asset.

sbu22 said:

Art - you mentioned Soltron - you prefer that over Stabil?

tilt - yep, good ole Crusader 454s.

Thank you all - maybe I do have an appreciating asset.

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Soltron and I go back 14 yrs of use. https://soltron-gtr.com/

Would take too long to write the plentiful and continued success Solrton has provided me with marine gasoline. According to the manufacturer it works very well for diesel too.

Will say... I believe in it due to cleanup of very old and dirty [water and bugs] 100 plus gallons of gasoline as well as the continual good condition of gasoline in our boats.

I've never used Stabil... may be a great product, I just have no experience with it.

BTW - GM Chevy 454's and 350's are great engines that when treated well last for a long time providing great service! I really luv em both!!

Soitron is new to me. Have to give it a try.

sbu22 said:

Soitron is new to me. Have to give it a try.

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Soltron

I sold my SeaRay Sundancer 245 Cruiser last year, it had been on the hard since 2004. Guy that bought it said it started right up. It had a 70 Gallon fuel tank I had filled just before going into a non-heated barn and was treated with Stabil and run on the ears for several minutes. Only issue he had was the water pump in the outdrive which I had told him I would change it before running it for any length of time.

For every 5 gallons of the old stuff you put in the tank, put 5 gallons of new stuff. The mix will work fine.

I knew I'd get answers here - thank y'all.