Bought some marginal, off-name gas in May 2004, truck sat until last Sunday. Three days, $300, gas burn on arm, replacement tank valve selector solenoid, replacement fuel pump and overhauled carburetor later, the truck finally again idles and runs normally. This instead of my fishing trip before freeze-up.

Buy good name brand gas, appropriate octane, and add fuel stabilizer if the rig will sit for more than a month. IT'S WELL WORTH IT!

 

After working in "marine" on and off over the years, have found that no matter what the time frame is from fill-up to start-up it's always a good idea to stabilize the fuel.Mainly to dissipate moisture that forms from temp.changes.

 

What's your favorite brand of fuel stabilizer?

 

I stored my Pontiac and I used Stabil. I put it in a full tank and stored it for 4 months. When I started it and ran it, it sputtered and spit, but it ran. I changed the fuel filter after I ran the tank out and checked the inside of the carb and it was as clean as the day I got it.

 

Used to use stabil also with no problems,now I use Amsoil.

 

I think that any gas will go bad if it is allowed to sit for six months. You have no idea what was in your gas tank when you gassed it up.

My '83 has 2 tanks. I fill them both, run the rear tank out first, then the front.

Float a loan, and I'm read to fill them both and start over again.

I've gotten crappy gas at big stations before, not to mention names.

 

I have found that keeping a full tank keeps the water problems is to nearly nonexistant. I have a '79 that stays outside all the time and is ran about once a month until winter when I use it to plow snow - keep tank full and no problems - starts right up and runs fine.

 

It all really depends on the end user and the climate where the vehicle is stored.

I do not use fuel stabilizers and I have three vehicles that sit for extended periods of time (garaged).

One is a 1991 Cadillac Seville...premium fuel only
Another is a 1982 Ford F-150 460...premium fuel only
Another is a 1972 Ford Gran Torino Sport...medium grade fuel

I keep the tanks full in these vehicles and start them about once every two weeks. They all use the same brand gasoline that rhymes with smell.

The climate where I live is very humid the majority of time and it would make good sense to use a stabilizer or dryer to keep the moisture and condensation levels down to a minimum. I don't use them because something that draws moisture must be disposed of, like a paper towel, dessicant, pellet, etc...

Since I am not a chemist, nor do I completely understand the physical dynamics of a drying agent, I am at a loss as to what happens to the collected water vapors. Do they float like a turd in the fuel until trapped by the filter? Then what...rust to the walls of the filter?

I have not yet had a problem, but that does take away from the fact that I may be headed toward 3 vehicle disaster, but these vehicles have been in and out of storage for the last four years and often sit for a few months at a time.

 

I am in Central Indiana - a real mixed bag of conditions - as I said, keep tank full and drive every month or so and no problems. I keep all my lawnmowers all winter with a full tank and fresh oil and they startup with no problem every spring. (I do take out the batterys and bring them inside to store for the winter)

 

I believe fuel stabilizers keep gum and varnish from forming in the fuel but have nothing to do with elimination of moisture. Keeping the tank full, however, prevents moisture from forming on the walls inside the tank because of the moist air inside the tank. There are alcohol based products sold to elimate moisture from inside the tank. Alcohol will mix with the water (gasoline won't) and allow the water to be "burned" along with the flamable alcohol. This is just my opinion and I don't remember if I read it somewhere or if if it came from the deductive reasoning ability of a shade tree mechanic.

 

The biggest contributing factor to condensation in a gas tank is sudden temperature changes.(Into heated underground parking, and then back out into sub-zero winter weather, on a regular basis, for example) Keeping the tank topped up, and using alcohol will help reduce the problem to a minimum. I go as far as adding a small amount of ATF in with the alcohol, more for it's lubricity than anything, as alcohol tends to dry out seals and rubber fuel lines as well.