I was advised to always use gasoline that hasn't been sitting around too long by the repairman when there are problems starting it up. Does the fuel lose it potency after being mixed with two stoke oil and if this is so, how long before it needs to be discarded?
What is "potency"?
It can lose volatility- the light-ends can vaporize and leave.
Liquid gasoline cannot burn- vapors burn. So fuel can become progressively more difficult to ignite in cylinder.
Keeping the fuel in sealed container, and in cool area, slows the loss. "How long" is anybody's guess.
I mix a gallon as I need it.
JI keep a can mixed, and every 2 or 3 years I have to mix some more. I've heard that, but never found it to be true. Keep the lid on the can tight.
"I was advised to always use gasoline that hasn't been sitting around too long by the repairman when there are problems starting it up. Does the fuel lose it potency after being mixed with two stoke oil and if this is so, how long before it needs to be discarded?"
I don't think the fact that it has oil added will make much difference in terms of longevity. I would try to use any gas up within a few months. If you think it will be sitting around longer than that, then I'd add some gas stabilizer. Even then, I'd try to use it up within 6 months or so. A lot depends on what temp it's stored at. Keeping it at moderate temps, it will be good longer than if it's in a hot garage in summer.
I use STA-BIL in the boat and for the weedeater and it does a good job...
STA-BIL Fuel Stabilizer should be used in any vehicle or power equipment that is used infrequently or stored for more than 60 days. Also, treat fuel in gas cans or storage tanks as soon as purchased so fuel will stay fresh. STA-BIL Fuel Stabilizer ensures quick, easy starts in all 2 & 4 cycle engines. It is safe to use in all cars, trucks, SUV's, boat motors, marine engines, tractors, motorhomes, motorcycles, ATV's, snowmobiles, jet skis, lawnmowers, snow blowers, tillers, weed trimmers, golf carts, power washers and generators. Use in gas, gas/oil mixtures, oxygenated fuel, reformulated gas, and diesel fuel.
One ounce of STA-BIL Fuel Stabilizer will keep 2-1/2 gallons of fuel fresh for 12 months. Using twice the recommended dosage will keep fuel fresh for up to 24 months.
Joe,
What you've heard is partially true but shouldn't be that great a concern as others have pointed out.
Actually, gas over time combines with a little water which does tend to 'weaken' it down but that can cause rust which is the main problem. The best way to avoid this is to keep your tanks full and cap tight. If there are no 'air pockets' then you won't have the problem with moisture combining with the gas. The second problem with 'old' gas is where it comes in contact with rubber components. It tends to break them down and gum up your engine jets. The Stab-alize solution that is sold helps to keep moisture out also but it prevents the gumming problem. It is more important to get this stabalized solution into the gas tank and carb of the motor than in your gas can. Hope this explains what you've heard about.
Joey
Joe wrote:
I have found that to be true with our Sears weedwacker. After about a year or so of sitting in the can, it becomes almost impossible to start if I use that same fuel. Fresh fuel always fixes the problem. If it isn't mixed yet, I just dump the old fuel in the Jeep to use it up. Doesn't bother the Jeep because its only a small part of the fuel in the tank.
Actually, it does-- it gums up the injectors and degrades the spray pattern. The reason you don't notice it is the engine is so powerful than you can't perceive the 5% performance decrement. But it does adversely affect it.
Edw.
When you mix a half gallon of old gas with twenty gallons of fresh, it is not a problem and the heavier hydrocarbons are going to be solvated and run right through not gumming anything up. However you don't want to pour that half gallon into an almost empty tank of a car.
A Great Big Thanks to everyone who replied and gave me such good advise
I really appreciate the help -
Here is the story. They should know.
Heh, anything goes here in 24hour.
Also, when a gas/oil mix sits long enough, a month or more, that oil and gas actually begin to separate into their heavier and lighter components. I know a lot of people are goign to say that's wrong, and I used to think so too, but it's actually. The mix, but the two, gas and oil, don't actually combine, so they separate over time. That's why it's often harder to start a gas-oil mix engine after it sits for a long time, especially if it hasn't had a good PM before the first start. Even with a good PM they still start harder that first time. That's because you usually have to store them with the carbs down to prevent spillage or fuel leakage, and the carb bowl tends to have the extra-oiled mix in it.
In addition, Sta-bil actually makes the engines a little harder to start, in addition to the oil business, whether it's a gas-oil or just a gas engine. I've used Sta-bil for years, since I discovered leaving, eg, lawn tractor tanks full over the winter resulted in better spring starts than emptying and running them dry. That was more years ago than I care to think about . Doubling the amont of recommended Sta-bil also isn't recommended and it does nothing but waste the stuff. Which also by the way, has a shelf life of its own once opened. Harder than acceptable starts can easily result from using too much Sta-bil. Been there, done that in fact: I always label what I did and when each spring/summer when I put away/get out the various machinery, right on the engine wherever there's a cool spot for the label, so it's not too hard to keep track of. Sta-bil, if you use enough of it, will actually prevent an engine from starting, but that takes several times the recommended amount, so it'd just about have to be done on purpose. How'd I get so smart about Sta-bil? I called the 800 number on their bottles and asked them. They sent me a whole white-paper on it! Been a faithful customer ever since!
Regards,
Pop
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