Does gas get "stale"?

[ecotourist]

Originally Posted by Driz
Try to keep the carb empty when it sits long term. That ethanol draws up enough water to corrode the inside of it. Once you tear a few of these small carbs down it's pretty obvious what that alcohol does inside the passages when it sits a long time. My snowblower when I got it had the bowl corroded in the very bottom. One spot even pinholed right through. That's the ethanol's magic legacy.

I run my Craftsman lawnmower's Honda engine out of fuel on the last use of the year. Is the carb completely empty at that point?

 

[Lubener]

Originally Posted by mclasser
Haven't been driving much lately but the Accord in particular has had the same tank of gas in it for nearly 8 wks.

Is that a problem? Does gas turn "stale"?

I got two cars sitting in the garage which I filled up last October because of the corona police. I am not worried. 20 gallons together will last much longer than the pint in your lawnmower.

 

[ZeeOSix]

Originally Posted by ecotourist
Originally Posted by Driz
Try to keep the carb empty when it sits long term. That ethanol draws up enough water to corrode the inside of it. Once you tear a few of these small carbs down it's pretty obvious what that alcohol does inside the passages when it sits a long time. My snowblower when I got it had the bowl corroded in the very bottom. One spot even pinholed right through. That's the ethanol's magic legacy.

I run my Craftsman lawnmower's Honda engine out of fuel on the last use of the year. Is the carb completely empty at that point?


Running the engine out of gas probably still leaves a hair of gas in the bowel, but probably better than not doing that procedure.

However, I've got a Craftsman lawnmower that I bought around 1980 (yes, it's over 40 years old) and have never emptied the carburetor out over the winter time (typically sits 6~7 months). It fires up every spring with no problems.

 

[DejaVue]

I started a car that sat for 3+ years. 87 octane. I think it was the clutch on the A/C compressor that did some rattling from sitting so long, but it started fine with the old gas in it. It drove fine, though I did baby the throttle until I used up most of that old half a tank and put some fresh stuff in.

 

[Avery4]

Leaving fuel in a car is much less of a problem than leaving fuel in a small engine because any modern car's fuel system is (or should be) completely sealed so no gasoline can evaporate and no moisture can enter. From my understanding the only reason modern gasoline goes bad is if the ethanol absorbs moisture from the environment or if its lighter and more volatile compounds evaporate, neither of which should be a problem in a modern car with a correctly functioning fuel system. That said, put some stabilizer in next time you fill up if that will make you feel better, it's not worth worrying about. I am actually testing Sta-Bil vs Star Tron vs untreated fuel to see if stabilizers work and if untreated gas goes bad, I have a thread on that experiment if you want to check it out. https://www.bobistheoilguy.com/foru...0/fuel-stabilizer-experiment#Post5381670

 

[DGXR]

I would only start to worry if it's been over 8 months and stored in a cold and/or damp environment.

 

[Avery4]

Originally Posted by DGXR
I would only start to worry if it's been over 8 months and stored in a cold and/or damp environment.

My understanding is that a low temperature is good for the longevity of gasoline, it certainly helps slow the evaporation of its more volatile components. Also, the humidity shouldn't matter if the car's fuel system is sealed (as it should be on any modern car). Temperature and humidity would be more of a significant factor if the fuel is sitting in a small engine or unsealed container though as heat accelerates evaporation and ethanol can absorb humidity

 

[michaelluscher]

I just put a Vulcan V6 powered Taurus back on the road
According to the receipt, back in 9/2018 it was topped off with 87, driven about 20 miles, then got parked with a blown brake line, and sat until about last week
Ran pretty badly TBH, I ran it nearly empty, dumped in 2 cans of B12 Chemtool, filled with 87, it's running about as well as a Vulcan ever does

 

[4WD]

Right … this was covered in a "treatment" thread and open systems like your boat are more susceptible.
Aside from small OPE … only fuel mess I ever had was a 35 gallon tank below deck that I had left about 8 gallons low and the fuel was already getting old from limited use. I had to flush goo from the OptiMax motor … and heavy dosed the top up fuel with both Stabil Marine and Techron. Took it for a couple runs down the ICW to keep making room for fresh/treated fuel.