View Full Version : the staleness of petrol...

06-22-2015, 01:10 PM
or gasoline,.. A question......with, in Europe anyway, the price of 'at the pump' fuel going up and down, and discounters, usually supermarkets selling at 15 or more cents a litre lower than the local gas station and 20 cents less than on the highway service stations....

Scenario. Off on the runabout tomorrow for a couple of days. 120 litres of on board gas, another 80 or 100 for the getting to the lake and back, maybe a spare 25 or 40 litre tank 'just in case'........lets say 250 litres at 1.50 a litre ( not sure exchange rate for to dollarUS, but whatever it's a lot money. If I buy at the discount station, I save 250 x 15 cents, about 40 beer tokens in any currency or about the price of a good meal for two, or 5 cases of beer.

Ok this isn't every nation's set- up, and so back to the opening query, if gas , for instance has doubled at the pump in the last couple of years, why don't I buy a tanker full maybe 25000 litres or5000 gallons, and stick it on the land and have cheap gas till I croak (not that I have 20k floating about with nothing to spend it on.) but even gold hasn't doubled in value in a year....
even if the figures aren't exactly fiscally sound to the penny, and storage regulations excepted, why not...
But when I had some trouble with a petrol engined bit of garden kit, a chainsaw I think, the repair guy said ' nothing wrong with the machine, but the gas smells old, I cleaned it out put in fresh gas and all's ok....'
Does petrol/gasoline get 'old'.....?


Norman Bernstein
06-22-2015, 01:17 PM
I can't speak for huge volumes in storage tanks.... but there is some degradation in small tanks. MOST of the problem is usually traced to what's left in the carburetor bowls, over a long period of time: 'varnish' builds up and clogs the jets... but it probably builds up in the tank itself, as well.

I solve this problem by adding a fuel stabilizer... on my motorcycle, I add some stabilizer at every fill-up.... and when I decommission the bike in the fall, I make sure I've got a full tank, add some stabilizer, and let the engine run for a few minutes to insure that the stabilizer has made its way into the carbs. Honda, in fact, recommends the use of stabilizer with every tank of fuel. As for decommissioning, there are two choices: one can decommission with a full tank and stabilizer, or one can drain the tank AND the carburetor bowls. Since draining the carbs in my motorcycle is difficult, I store it 'full' for the winter. My snowblower, on the other hand, spends the summer completely empty, since it's easy to drain the gas tank, and then run the engine until the carb bowl runs dry.

In either case, both the bike and the snowblower start immediately, and easily, after thier 'off-season'.

Here in the US, there's a popular fuel stabilizer called 'Sta-bil' that I use... I think it's mostly methanol, which helps to absorb any water condensation.

Jim Bow
06-22-2015, 01:19 PM
Definitely, and old gas smells like varnish.

I was once given a motorcycle that had sat in a garage for 12 years. When parked, it had about 3/4 of a tankful.
I pulled the tank and poured it into a bucket. First out was a clear liquid, then a pure black inky substance, followed by a thick smelly syrup of something. Inside the tank, the bottom was nice and clean (after a rinse with parts cleaner) and the top was rusted. The carbs were glued with brown gunk and soaked for hours in cleaner before being rebuilt.

Old gas is bad gas, fuel injectors are especially susceptible.

06-22-2015, 01:19 PM
I left a car in the garage with a half-full tank for eight years. Chucked in a new battery, and it started first time.

P.I. Stazzer-Newt
06-22-2015, 01:28 PM
There are a few fuels which are unconditionally long term stable - pump gasoline typically isn't among them - especially so with US gasoline.

Take a look at Aspen's Alkylate fuels such as 4T.


06-22-2015, 01:43 PM
Bigger engines with bigger carburetors like cars handle sticky old gas quite well although how old is too old I don't know. The problem is mainly with small engines such as portable outboard boat motors that have to control the flow of such tiny amounts of fuel.

06-22-2015, 04:26 PM
The volatiles in gas are the first to go (evaporate), so even if you use a good stabilizer like Seafoam, eventually the gas gets old. I have had stabilized gas stay useable for up to four years. I doubt that it was as efficient (powerful) as fresh gas.

And wouldn't the costs associated with storing such a large volume of gas offset the savings? Just the insurance would be a huge expense.