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That strange that you had water when the exhaust is a new one. Maybe it is humid air from inside the house that condensed in the pipes when you took them outside. Do you usually have a humidifier running in the house?

If not, I don't know why it would have been from gas since you barely ran the thing. According to chemistry and for simplicity's sake, I'm only going to calculate this out for octane (since a gas molecule is between 5 to 12 carbons long), you would assume that:
2 C8H18 + 25 O2 --> 16 CO2 + 18 H2O
This says that for each molecule of gasoline you burn, you would get around 9 molecules of water vapor in a complete burn. With a density of gas about 703 grams per liter (at STP), octane's molecular weight of 114.2, 3.79 liters per gallon, water's molecular weight of 18.0, and water's density of about 960kg/m^3 at just below boiling (since all water would leave the engine as steam), you would expect that:

(1 gallon octane) x (3.79L/gallon) x (703g octane/L octane) x (1mol octane/114.2g octane) x (9mol water/mol octane) x (18.0g water/mol water) x (1kg/1000g) x (1m^3 water/960kg water) x (100^3 cm^3/m^3) x (1mL/cm^3) x (1L/1000mL) x (1 gallon water/3.79L) = 1.04 gallons of water

Basically, if I remember my chemistry, this says that for every gallon of gas you burn, you would get 1.04 gallons of (liquid) water. This is a high estimate though, since you wouldn't get a complete burn, and the water comes out of the engine as vapor and not liquid, so the only liquid you would see is what condenses on the pipes. Let's say that 99.5% gas in an engine is actually combusted with 0.5% remaining intact (this is a complete guess since I have no idea on the real number, but I would assume much lower combustion percentages would make your exhaust smell like gas) and that 4% of water vapor actually condenses when the exhaust piping is cold (once again, another guess; could be much higher), giving us an estimate of 0.04 gallons of water condensed per gallon of gas injected into the engine.

Finally, with each revolution of the engine with the fuel injector working at 39#/hr, assuming it is a V8 engine and that, from your other thread, lets say, 4 minutes total running time with an average of 1500rpm idle (I stole the base equation from Wikipedia's fuel injector page):

(Fuel flow rate) = (2.0 ms/intake-stroke) × (hour/3,600,000 ms) × (39 lb-fuel/hour) × (4-intake-stroke/rev) × (1500 rev/min) × (60 min/h) = (7.8 lb/h) x (1hr/60min) x (4min) x (453.6g/lb) x (1L/703g) x (1gallon/3.79L) = 0.089 gallons of gas (in 4 minutes)

(0.089gallons octane) x (0.04gallons water/gallon octane) = 0.004 gallons of water

So, this SHOULD mean that in the time you had your car running, 0.004 gallons, or about half a fluid ounce, of water had condensed on your exhaust pipes, which sounds like way less than what you were talking about.

However, since you mentioned your engine had been flooded with gas a couple days ago, much more gas than predicted could have been burned and would have produced more water, so maybe that is where your extra water came from?

And as far as gas breaking down in the tank to form water, I would doubt it. While I am guessing gas would break down into CO2 and water in the presence of oxygen, I really wouldn't think it would produce a noticeable amount of water in only half a year, especially since the winter temperatures would slow its oxidation.

Like I said above, some of these numbers I assumed from what I thought would be reasonable for the situation, and the gas you burned may very well have caused the water.
 

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Oh and one more possibility: when you turned off the engine, more water vapor could have condensed once the vapor was no longer being pushed out of the pipe (and would be more or less sitting in the exhaust pipes until it either a) worked its way out the end of the exhaust system or b) condensed on the pipes)
 

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It's a chemical reaction to keep the molecules from reacting with air over time. It's magic:headscratch:. All I know is it does work. I've been storing motorcycles during the cold season for almost 40 years. I learned the hard way that gasoline turns to a varnish like substance as some of the chemicals evaporate. Carb jets and needles plug up and require a rebuild. Stabil keeps it from happening.
I would think it would change the physical properties of the gas by keeping the byproducts from the gas' evaporation in a dissolved or combustible state.

Since gas is pumped from the ground, it must be distilled and purified. While the end product IS very pure, traces of petroleum-related "gunk" will still remain in the product. Since the main constituent of gas is volatile, it will evaporate fairly quickly if given the chance. As this happens, the I would assume the proportion of the gunk in the gas raises since it stays at roughly the same amount in the tank while the amount of gas lessens from evaporation.

When this is burned, it would create more deposits since the actual gas burns quite easily compared to the gunk in the conditions of an engine.

My guess would be that stabil would work by dissolving and forming an azeotrope with the gunk where it can be carried away in the exhaust with much more ease than if the stabil wasn't present.
 

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Are you related to Mr. Wizard?
I'm kinda embarrassed, but I had to Wikipedia who that was :hihi: (yeah, yeah, yeah: "kids these days" and all that kind of stuff).

But no, I'm not related (plus he would be either my great or great-great grandfather...:headscratch:). Bill Nye is the next on my "People to Check for in my Family Tree" list, though :scratchchin
 
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