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Discussion Starter #1
I buy my gas at one of 2 service stations. (I haul my gas into the woods). The places where I buy my gas are busy so the gas does not sit around. I buy regular 87 octain gas like my manual tells me. Should I still be worried? What do you mean by "bad gas"?
 

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I think you might be referring to oxygenated fuels or fuels with ethanol added, like most of the crappy fuel we get down here. In theory, by using ethanol, or oxygenated fuel, you get a cleaner burn in the cylinder by a more "complete" combustion, and hence lower emissions (according to the tree huggers). However, the fuel starts to seperate with weeks. Also, the ethanol dries out gaskets and rubber seals when you leave it sitting. I don't know what you have in Canada. Is this what you are talking about?
 

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Another bad issue with the ethanol blended fuels is that they attract water. Not good in anything. But by saying "bad gas" I think you're talking about gas that has sat for too long or the stuff you get from chile. Any gas whether or not it is ethanol blended or regular will go bad after a period of time. How long depends on the quality and type of gas as well as the container it is stored in and where it is stored. Personally I would not let the gas stand for more than a month. Thats just me. Some people will still use it but I'll dump it in my truck and mix it with some fresher gas. Bad gas could also be getting gas that has water in it from a leaky holding tank.
 

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i hate tree huggers and democrats. oh, al gore as well.
 

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I had bad gas once, I think it was all of the bean burittos I ate: :) :D
 

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The only gas I buy is Amoco, if I can I get non-oxygenated, but thats hard to come by at many stations.

Oxygenated Amoco is better than other gas because they don't use ethanol to oxygenate their gas they use MTBE (Methyl Tetra Butyl Ether).

Ethanol is not good in your gas because it attracts and holds water (100 times more than MTBE can) so any station could dump in barrels of water in their gas and it won't separate from the gas. MTBE (only at Amoco), holds virtually no water compared to ethanol and it won't dry seals out and there is more Power per gallon (BTU's) because there is no ethanol.

GO AMOCO!!!
 

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If you don't stabilize your gas, it will start to degrade within a month. Stabilizer will keep your gas fresh for at least a few months.

By degrading, the octane level decreases. So, if you need to run 87, buy 91. Store it, and by the time you use it, (within a couple of months I assume) it should still be fine.

Probably a little cheaper than buying stabilizer.

FishHog
 

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ooo is that what that MTBE stands for, thats at the gas station/convient store that i always fuel up at. good gas then.
 

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Fishhog, no offense but I think youre wrong on the octane degrading when the gas gets old.

91 octane costs more and is better gas because it is distilled more than 89 or 87 octane. This process takes more time and money to do that's why its more expensive.

As for degrading of gas over time, it doesn't get distilled any further, the chemical composition breaks down creating a sticky alsmost gum like texture.

When this happens it gets stuck in injectors, filters, fuel lines and pumps.

Letting 91 octane sit in your sled for a year or 6 months will be just as bad for your engine as 87.

So always use stabil or sea foam to preserve your gas, although the stabilizers will only last for about 3months.
 

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Originally posted by sledcrazy@Oct 31 2002, 04:39 PM
ooo is that what that MTBE stands for, thats at the gas station/convient store that i always fuel up at. good gas then.
What????
 

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Methyl Tertiary-Butyl Ether (MTBE)

is an octane enhancer. Basically an additive to low grade gasoline to enhance the octane.
 

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ya i was wondering what it stands for.
 

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Discussion Starter #13
We don't get the blended or oxygenated gas way up here. The gas I buy comes from the Irving refinery in Saint John NB. Hell we don't even have bean burittos on the North Shore. :hallo2:
 

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I don't know if this is true or if I am even explaining it right but someone once told me that as gas sits it absorbs oxygen and because more oxygen will make it more flamable this screws with the octane rating. Since octane is basically what controls the burn this makes sense because adding to the oxygen content of the fuel will make it burn quicker. According to this guy one of the things stable does is rise to the top of the tank and form a layer that prevents the fuel from absorbing the oxygen in the air that is in the empty parts of the tank. Thats supposedly why if you fill your tank to the rim the gas will not go bad as easily because there is no air for the fuel to absorb oxygen from. Has anyone else ever heard of this?
 

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I'm not offended at all Becker. I've been know to be wrong once or twice before. :p

But I don't think were really disagreeing. While your right, higher octane fuels are distilled more, and thus cost more. And they definitely will breakdown also. Eventually varnish will form, this is very true.

However, the amount of varnish that forms in a couple of months is minimal, and should not affect your sled, if you store leave the tank full for a couple of months. What will happen however, is that the octane level will degrade, which could lead to predetonation, and burn down.

If your compression is low enough to run 87 octane, then a couple month old 91 octane will still be ok. Your fuel filters will remove any deposits that may have formed. I however have left gas sit, for 6 months, with minimal varnish formation.

However, a couple month old 87 octane, may be down to 83-84 range, and cause you burn down.


As for stabilizers, I'm not sure how they chemically function, but I do not believe they form a layer on top. Would seem to me, that you would eventually end up with way too high a concentration of stabilizer in your tank if that was the case.

The main reason why you fill a tank to the top, is to minimize the air space, which can lead to condensation during temperature changes, causing the accumulation of moisture.

OK, now I'm tired of typing.

FishHog
 

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The reason you should fill your tank up to the top is to prevent condensation. Water from the air in the tank will condense and drip into the gas. Now you open yourself up to all kinds of problems.
 

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What FishHog says I think was pretty much stated in an article I read in SnowTech some time ago. I remember reading that there's supposedly a half-life to gasoline and it hits this half-life after a month of sitting. What that means, I don't know but it sounds like you don't want to leave it sit for much more than that time without some sort of stabilization.

I thought I heard that MTBE was bad and to stay away from any gas that contains it. Has anyone else heard that or was that some story made up by the Ethonol guys?
 
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