Short Gasoline Life?

Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Ok this is more a question of truths or mis-truths, here's my story.

For years and years I have been using Stabil in gas tanks. My father collects antique cars and also does this as they don't get used all winter, nor much in the summer for that matter.

Stabil has worked for me, or maybe it has not, I don't know but I still add it. In the last couple of weeks I have, again, for about the 25th year had a chance to prove to myself that old gas is not necessarily bad.:confused:

Example #1: In 1996 I purchased a Generac generator for our house. We used it during the ice storm in the 90's, it got used hard, and since then has maybe had 40 minutes of use once every other year or so. Fortunately or unfortunately we live down the street from a US Senator and get the same power feed so we rarely ever lose power.

The old gas that was in it last week when I fired it, due to the ice storm, up was still 1996 gas!!!!! We lost power, actually quite a long loss for us, and the generator ran perfectly & smoothly with no smoke or issues. I ran an additional 15 gallons of fresh fuel through it which I too stabilized. The only thing I have ever done to this generator is use it, add Stabil and then while running turn off the fuel supply valve to run the carb out of gas. I did also change the oil after break in but that's it... 1996 gas!!!!!!!!!

Example #2:
My snowblower is now over 20 years old with a Tecumseh Snow King engine. It sits for about 8 months per year, every year, with last seasons gas in it. In twenty years I have changed one belt, LOTS of 5/16" shear pins, and the oil just twice. Just for grins I replaced the ORIGINAL spark plug yesterday. It made no difference and it still runs perfectly, as it did with the twenty year old spark plug. In the spring, for summer storage, all I do is add Stabil, start it and turn off the gas tank valve and run the carb dry.

Example #3: My 2000 Johnson 4hp. twin cylinder two stroke also sits every winter with last seasons gas and Stabil. Even though this is a two stroke I have yet to replace the plugs. All I have done to this motor is to replace the impeller, use Stabil and run it dry via the gas shut off valve. In eight years this motor has not so much as hiccuped..

Example #4: My fathers 8 classic cars none of which have shown any sort of detrement or excess carb junk in the 40+ years he's been collecting add more to this question? He I I have torn into numerous engines and carbs over the years and found more gasket/o-ring issues than any sort of varnish or gum..

So my question is this. Does Stabil really work that well or is it just another scam we've bought into? If I left the gas from 1996 in my generator, well beyond even the what Stabil label states, does gas really ever go bad if it still runs perfectly with no issues?

I read of lots of boaters panicking over old gas and I've never panicked and also never ever had a gas related issue??? Perhaps I'm just very lucky??

P.S. I have seen the inside of the carb on my Johnson OB after some friends tipped my POS Wakler Bay near shore and dunked my motor. It looked like new in there and this was after six seasons of "bad" gas..

What do you guys think and has anyone else been as brave or dumb as me in trusting "bad" gas..?
 
Jul 24, 2006
628
Legnos, Starwind, Regal Mystic 30 cutter, 22 trailer sailor, bow rider NEW PORT RICHEY, FL
bad gas

i think you are extreemly lucky. I live in florida with high heat and humidity and i can attest that gas does go bad. Your use of stabil is very prudent. Just try not using it in one of your applications and see what happens!
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Re: Bad Gas???

I have a lawnboy mower that gets new gas when the 2 gallon can goes dry. I run it until fall and shove it into the shed. In the spring I clean the air filter, give it a shot of starter fluid and mow the lawn. For the rest of the summer that's how i use it. No starter fluid after the first start up in the spring. Whatever gas is in there is what is runs on. It is going on to twenty years now.
 
Sep 25, 2008
7,077
Alden 50 Sarasota, Florida
Re: Bad Gas???

This may be another example that proves the theory - perception is reality.
For those who use stabilizers in gas and have no problem, their perception is that stabilizers work.
For those who don't use stabilizers and have no problem, their perception is that stabilizers are all hype and
For those who have problems regardless, any perception is possible.

So what conclusion can be drawn? Without unbiased and objective side-by-side comparisons and discounting marketing ploys entitled "tests", perception rules.

The more important question might be why tempt fate for the few bucks a stabilizer costs?
 
Nov 22, 2008
3,562
Endeavour 32 Portland, Maine
Re: Bad Gas???

There was an interesting item on the radio the other day pointing out that your generator or snowblower produces about 100 times more carbon monoxide than and idling car which is why it is so dangerous to warm them up or run them in a garage.

There is a lot of sophistication in engines that can run so cleanly so fuel quality is more important. Those simple "lawn mower" engines will burn almost anything. Newer gas formulations are also much more stable. You might not have the same luck with the gas you put in today.

I would keep adding the snake oil.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
I would keep adding the snake oil.
I'm going to keep adding it, hell $6.00 gets you a life time supply! I just question whether or not gas really does go bad that is being used for non-fancy engines like simple outboards, mowers, generators, the A-4 and pre-pollution control antiques??
 
Sep 25, 2008
7,077
Alden 50 Sarasota, Florida
I'm going to keep adding it, hell $6.00 gets you a life time supply! I just question whether or not gas really does go bad that is being used for non-fancy engines like simple outboards, mowers, generators, the A-4 and pre-pollution control antiques??
Your answer may depend more on how one defines "bad" as there is no conventional criteria. Clearly, the more volatile components of gasoline which the stabilizers are intended to "stabilize" and which are critical to the combustion process are preserved but the issue then is how much and how fast - neither of these criteria are commonly accepted measures either.

The "non-fancy" engines to which you refer can be both high or low compression so that too becomes a variable as does simple luck, the conditions under which each engine is stored, how well it's tank vents, etc...

To put it another way, there are lots of questions having multiple answers depending on context but they all go away with the $6 investment as you say.
 
Oct 2, 2006
1,517
Jboat J24 commack
I due use stabil so it must be good :)

I have done fine with all my small motors except the snowblower which i got used and had to soak it and install a carb kit

I use the blower when it snows and it started on the second pull this year after sitting 8 months :)

The rideing mower starts 2 times a year to cleanup leaves and i dont even seem to need to charge the battery

My weed wacker and chainsaw also seem fine other than some really old fuel line for 2 bucks
 
H

HAL

gas

I have experienced almost the exact same situation. Ice storm 96, generator, Stabil, run dry to store, not much use since, start occasionally to test, add a little gas. We used it during the recent storm and gas was no problem, plug was fouled and replaced. Essentially the gas was very old compared to what is contemporarily said about gas getting stale in months. I even let the tank run low leaving lots of air space, which I usually don't do, because if the gas was stale it would be easier to deal with. I have wondered about whether the coincidental use of winter or summer gas might effect its longevity. Other vehicles and machinery that sit for long periods with the use of Stabil also have had no gas problems. Started using Stabil over 20yrs ago and still do. I don't know what would happen without it.
Another wrinkle is I now use high test in everything after a small engine mechanic said carb innards, which he sees allot of, stay cleaner with high test than with any other regime including carb cleaners and additives.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
To put it another way, there are lots of questions having multiple answers depending on context but they all go away with the $6 investment as you say.
No, my question is, does the Stabil actually do anything seeing as the label states it too has a shelf life which I have exceeded many times? Not that I'll stop using it, it's very cheap, but I do question if it's like a vitamin beating cancer... I still take the vitamin too...:doh::doh:
 
Nov 6, 2006
9,885
Hunter 34 Mandeville Louisiana
Bad Gasoline

OK here is some stuff about fuel stabilizers..Most are a suspension of BHT/BHA in a light oil dispersant like kerosene. Below is how they work.. From working in the industry for many years, I know that the gasoline of today is very different from what we used to make. Specifically, it is made of components that have a much higher “gum index” (they want to turn to polymer) than what was used 15-20 yeas ago.. The change started about the time that crude prices began to rise because the companies were challenged with making usable gasoline from uuuhhhhhh “opportunity crudes” which were messy and priced far below the published price for crude. It is profitable and the practice continues at a more advanced pace than before. Gasoline is more affected than diesel is, but both are of considerably less quality than they used to be because of the poor quality crudes and other components (like small amounts of waste from chemical operations). I use fuel stabilizers in my fuels that will sit around for a while before being burned. Even with stabilizers, the octane/cetane number decreases slightly with storage but most engines won’t know the difference. The 24 month max storage number that shows up is a good one and is conservative. Another note: synthetic two stroke oil does not gum but the regular one does with a vengeance.. Still use a stabilizer in either, but you can help yourself by buying straight synthetic for two stroke use. Ohhh the rate of gum formation changes a lot with storage temperature.. cooler is better!
BHA and BHT are antioxidants. Oxygen reacts preferentially with BHA or BHT rather than oxidizing fats or oils, thereby protecting them from spoilage. In addition to being oxidizable, BHA and BHT are fat-soluble. Both molecules are incompatible with ferric salts. In addition to preserving foods, BHA and BHT are also used to preserve fats and oils in cosmetics and pharmaceuticals.
What foods contain BHA and BHT?
BHA is generally used to keep fats from becoming rancid. It is also used as a yeast de-foaming agent. BHA is found in butter, meats, cereals, chewing gum, baked goods, snack foods, dehydrated potatoes, and beer. It is also found in animal feed, food packaging, cosmetics, rubber products, and petroleum products.
BHT also prevents oxidative rancidity of fats. It is used to preserve food odor, color, and flavor. Many packaging materials incorporate BHT. It is also added directly to shortening, cereals, and other foods containing fats and oils.
 

Rick D

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Jun 14, 2008
7,132
Hunter Legend 40.5 Shoreline Marina Long Beach CA
California Experience

Maine, I'm not sure if the Republic of Southern California experience is relevant, but my and others experience is that our gasoline blend (which is unique, I believe...) has far more limited storage life over the last five years or so. In my experience, six weeks to two months is about it, and even two-strokes and utility engines won't run (or well) after that and are bears to start w/o an additive. Of course, those engines are also low-emission certified over the last few years too, so they may be part of the issue. Anyhow, most of us are now regular users of fuel extenders now (and were not before).
 
Jun 4, 2004
844
Hunter 28.5 Tolchester, MD
Re: Bad Gas???

I would presume that the 10% alcohol listed on our local gas pumps may also have an adverse affect; attracts more moisture, etc. I've routinely run the last gas out of carburetors and disconnect the fuel line )previous outboards) and use the gas in the mower -- start fresh again in the spring including new spark plug and oil change; and that was before the added alcohol.
 

JerryA

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Oct 17, 2004
549
Tanzer 29 Jeanneau Design Sandusky Bay, Lake Erie
Re: Bad Gas???

I've experienced the same thing as Maine Sail and I don't use Stabil, maybe I should, but I don't. I fired up my generator this summer for the first time since 2005. It started right up and ran fine. My sons Jeep sat for 5 mths this summer with 3/4 of a tank. I started it a few weeks ago in 30 degree weather. Started and ran just fine. I mix up a gallon of 2-cycle gas each time for my leaf blower & weedwacker. It takes more than a year to go through that gallon, and I never have any problem.

That being said, I've seen the gunk in carburetors from bad gas. I remember having to dunk one in solvent for a day to get the float free from the bowl. I had a stuborn neighbor once that couldn't get an old mower started that someone had given him. I smelled the gas, and told him it was bad and would not burn. After a weekend of dinking with it, and never removing the old gas, he ask me if I wanted it for parts. Of course I said yes. I pulled the tank, emptied it, reassembled with new gas. If I remember right, it started on about the 5th pull. I mowed grass with it that afternoon. So gas will go bad, but I don't really know how long it takes.

JerryA
 
Jun 5, 2004
209
- - Eugene, OR
Re: Bad Gas???

According to my mechanic, the oil companies have changed the forumlation of gas in ways that give it a relatively short shelf life. The question came up because of problems with motorcycle, outboard and mower/stringtrimmer engines that refused to start after not being used for a while, but which started right up when the old gas was removed and new gas put in. On that basis, I now believe that yes, gas does go bad over time, and annoying quickly at that. If you have been using modern gas, stored with stabilzers, I would have to accept that as empirical evidence that they work, and thank Claude for his explanation.
Jim Kolstoe, h23 Kara's Boo
 
Oct 22, 2008
3,502
- Telstar 28 Buzzards Bay
Re: Bad Gas???

Maine Sail—

While the Stabil has probably helped prevent varnish and gum formation over the years, you're going to find that the new ethanol blends are far less stable than the older MTBE formulated gasolines, due to ethanol's hygroscopic tendencies.

There is a new formulation of gas stabilizer that is specifically formulated for ethanol blend gasolines, and if you're using E10 gasoline, which is what most places sell nowadays, you should probably switch to the new formulation of gas stabilizers.
 

RichH

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Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
Re: Bad Gas???

Stabil like many other stabilizers/inhibiters really do work.

Try this test for yourself: take two small glass jars fill with gasoline, add stabil or other stabilizer one and add nothing to the other, then, ... leave the seal/cap slightly 'ajar'. Leave for 6 months and examine the two. The results will be somewhat startling as gasoline only has a 'shelf-life' of 30-60 days.

With gasoline the decomposition is all dependent on how much oxygen is mixing into the fuel ... back feeding through carburetor bowl vents, etc., there to absorb into the fuel, etc. The predominent decomposition sites are in the bores of the teeniest airbleeds and metering jets, etc. or where there is a relatively large contact area of metal to fuel.

Many of the oil-based or oil containing foodstuffs you eat are stabilized by the same type of chemicals (polysorbate-80k, etc.) to extend the time when they become 'rancid'. So, you also may want to make your own mayonnaise add some ps80 to one jar and not the other .... then see what happens. Yup, the stabilizer really do work.