Ethanol in long term storage (standby engine)

[Harry]

Without getting into a huge political rant about why there is 10% ethanol in our current regular gasoline, I have a question about the use and storage of this fuel. This isn't about a chain saw or a weed whacker that can be drained after use, but it is about secondary vehicles with 20 gallon or 75 gallon fuel tanks. It simply isn't practical to consider draining these tanks and storing them empty.

We are stuck with ethanol in the supply, so what if anything can we do to help preserve this fuel in the tank for a year or so?

[Motormowers]

You need an additive with an enzyme like Star-Tron. I havent found anything else that works for me.

[Smokin Bob]

Harry:

Here in Illinois, we have had 10% ethanol in our fuel for about 15 years now. When I need to store this fuel long term, I have always used Sta-Bil by Gold Eagle Products. You can generally find it at any hardware or auto parts store. Mix it with the fuel according to the directions. I have stored 20 gallons in my stand-by generator tank for as long as two years and it fired up and ran with no problems. I also use it in my Harley to store over the winter with the fuel tank full. The key is to add the Sta-Bil as soon as you buy the fuel, while it is still fresh. Adding it to old fuel will do no good, as the lighter elements of the fuel will have already evaporated.

The only problem I'm aware of with gasohol is that if it is stored long term in certain older fiberglass tanks which were not designed for it, it can leech out the resin which will literally melt the tank and create a gooey mess in what's left of the tank. Steel, aluminum, iron, etc. should be fine, as long as you keep the tank full so as not to allow condensation on the walls.

Just my two cents; hope it helps!

Bob

[Harry]

I have steel tanks.

Given the cost of the fuel, I suppose that I shouldn't worry about the Stabil cost to treat 50 gallons.

[Craig A]

Granted, Sta-Bil isn't cheap......but it works and I can verify that year old, and older, treated gas works fine.
It's a lot easier and less expensive than having to drain and dispose of unsalvagable gas.......

[Motormowers]

If you go with the garden variety treatments then use the B&S stuff. Its better than Stabil hands down and at least tells you how long the fuel will stay treated depending on dose-age right on the bottle. One or two years. Stabil does not!

[Andrew Mackey]

You MUST have a sealed tank to keep that fuel long term. 10% alky gas is hygroscopic, that is it WILL absorb water out or the air. On humid days, this will degrade your gas, wether you have stabil in it or not. The more gas volume the lower the rate of decomposition, unless the container is not sealed. Fuel in a large tank is not the real problem. Fuel in the fuel lines, and the carb is a big problem. Especially in the carb, the fuel will volitize - it will evaporate the volotile componants, like Iso-butane, iso-propane, and the alcohol, that is added to the base chemicals that they call gasoline. Stabil will slow the breakdown and evaporation process, but will not completely stop it. It will not stop the water absorbtion, nor the galvanic actions started by the now altered alcohol, attacking the brass, aluminum and steel parts of your fuel system. It is important to run the engine for at least 15 minutes, weekly, in order to clear these contaminated fuel componants out of your carb. If the engine is not to be run at all during the off period, then the carb, fuel pump and fuel lines to the carb MUST be purged and emptied if you want to have the engine in running condition when it is needed. Another added attraction now being noticed in engine shops is the fact that there is now a bacteria that is attacking the alcoholized gas in storage. Sthil now recommends that the 10% fuel NOT be kept for more than 30 days MAXIMUM. It seems that there is a bacteria present in the fuel that will gum up the new carbs, if old fuel is being used. It slimes up the passages, occludes the carb fuel ports, thus leaning out the fuel/air ratio enoigh to cause engine damage or failure. The bacteria also degrades the fuel's ability to burn efdfeciently. Sthil will not warrent repair engines found with this problem! I know Sthil uses 2 cycle engines, but the fuel problem is also the same in 4 cycle engines as well.
Andrew

[pegasuspinto]

if it's a modern vehicle (most anything made since 90 or so) the fuel system, if right, will be plenty well sealed up for 10% blends. I've never had a problem in a newer system that's sealed up right, but it doesn't seem to like being exposed to the air at all. older cars, gas cans, equipment tanks are usually vented to the atmosphere directly, and those are the systems to watch out for. read something that a blend will asorb water until it falls out of solution with the gasolene, seems ethanol saturated with water will NOT mix with gas. then you are left with watery ethanol on the bottom, and pure gas on top.

Robert

[Motormowers]

Ive been using this Star-Tron stuff with great luck. Over the weekend a friend gave me this stuff called Pri-G. Its supposed to turn stale gas pump fresh almost instantly?? Has anyone ever heard of it? Its says its for ethanol fuels also.