How long until gasoline goes "bad"?

[blurredvision]

I filled up my 2-gallon gas container probably around July or August of last year. I use the gas for the lawnmower, and since I have a small yard, those 2 gallons go a LONG way. Anyway, I just purchased a new 4-cycle gas trimmer for the upcoming season, and I'm itching to rev it up and make sure it works.

Since this gasoline is at least 7-8 months old, do you think it'd still be good to use, or should I just pour it out and get fresh gasoline? I know you can buy some kind of additive that is supposed to help gasoline be stored longer, so I didn't know if gasoline had a finite shelf life, and what it was.

Thanks!

 

[spidey07]

At least 2 years. You're fine.

 

[joesmoke]

Ive had a few gallons of supreme sit for 4-5 months after a dirtbike crash... still worked fine, just shook it up first (no idea if that does anything though)

 

[blurredvision]

A Google search seems to give many differing answers, so that's why I asked here. I just don't want to dirty up my new trimmer with old gasoline, but then again, it's not like heading down the street and getting $7 worth of "new" gasoline will break me . I just don't know where to get rid of what I have if it's recommended that I not use it.

 

[spidey07]

A trimmer mower is not a 32 valve DOHC V-8. It's a simple motor. Don't worry about it.

 

[DrPizza]

If in doubt, put it in the car's gas tank and refill the trimmer with fresh gas.

 

[MrPickins]

Originally posted by: DrPizza
If in doubt, put it in the car's gas tank and refill the trimmer with fresh gas.

Winnar!

 

[KB]

I have used 2 year old gas in my lawn mower and 1.5 year gas/oil mix in a chainsaw with no trouble. Mix it with some fresh stuff if you are really worried.

 

[blurredvision]

Originally posted by: DrPizza
If in doubt, put it in the car's gas tank and refill the trimmer with fresh gas.

That's thinking outside the box . I've only got about half a gallon left, so that's what I'll do. A fresh 2 gallons will last me through the summer. And here I was wondering where I'd pour it out .

 

[Atomic Playboy]

Why does gasoline go bad? It's just hydrocarbons that have been sitting around for millions of years. I'm assuming it has something to do with the refining process; but what would cause it to stop functioning as a fuel?

 

[seemingly random]

The volatility of gasoline decreases over time which is not a big problem. The real problem is condensation (water) that might occur in the container. Some engines have more sophisticated fuel filters than others. This is why, if there is doubt about suitability for a mower or trimmer, I'd put it in a car. If the container isn't full, I've added premium successfully.

 

[Crucial]

I'd say the real problem is soluble gum. When gas gets old it evaporates leaving behind a sticky goo. This can clog up jets and passages. Just add Stabil to the gas when you fill up the can and it'll last till the next season just fine. Double dosing the stabil will give it a 2 year shalf life according to the manufacturer.

 

[BoomerD]

Originally posted by: DrPizza
If in doubt, put it in the car's gas tank and refill the trimmer with fresh gas.

Ding! Ding! Ding!
We have a WINNER!


I do this every year at least once. Running a small amount of stale gas in a tankful of "fresh" gas won't hurt your vehicle, nor will you even notice, but running a tankful of stale gas in your lawnmower may have you pulling, and pulling, and pulling the cord trying to get the *&% #$%Y^ sumbitch to start for hours...

Even if you add gas stabilizer to the container, gas starts to get stale after a month or so. YES, it may still be fine next year, but why fight it? Just dump it into your tank and get fresh.
BTW, only buy as much as you're going to need for a short time rather than buying 5 gallons at a time for the lawnmower.

http://www.straightdope.com/columns/060825.html

 

[K1052]

Originally posted by: Crucial
I'd say the real problem is soluble gum. When gas gets old it evaporates leaving behind a sticky goo. This can clog up jets and passages. Just add Stabil to the gas when you fill up the can and it'll last till the next season just fine. Double dosing the stabil will give it a 2 year shalf life according to the manufacturer.

Yep, Stabil is the way to go. We always add it to the fuel for the lawn equipment near the end of the year.

I also used to keep 30 gallons of regular (non-ethanol) gasoline in 5 gal steel cans as a reserve. Stabil kept it fresh until I rotated it out after a year.

 

[antyler]

Take a match to it. If it lights up, its still good.