Can petrol go off

google says 60 days in a saled container at 20 degrees , I dont believe this to be honest , surely no one believes fuel from the refinery gets to the consumer with in 30 days ?
deff not at the moment
 
The boat project I have just got has a very large aluminium tank. And the floods thing is nearly full. At a guess it’s a 200l tank.
The guy I got it from
Is a first class bu#####tter. He said it’s a year old. But so far he lied about everything so I do t believe him about anything.
But I would cry if I dumped £250 wort of petrol. Any thoughts.
 
yes, to a certain extent and over a prolonged period , say 1 year , it will loose some of its octane , ( i believe that is correct ) , it will still run the engine but not so well.
 
petrol does go off if exposed to air. If the tank is pretty much full and sealed it will last a long time. However if left part full with lots of air around it the lighter components seem to evaporate/oxidise.
 
darren west said:
The boat project I have just got has a very large aluminium tank. And the floods thing is nearly full. At a guess it’s a 200l tank.
The guy I got it from
Is a first class bu#####tter. He said it’s a year old. But so far he lied about everything so I do t believe him about anything.
But I would cry if I dumped £250 wort of petrol. Any thoughts.
Click to expand...
If the boat is running with it, then as you use it, keep adding some fresh petrol to dilute the old.
 
There will be loads of people who google things and quote lots of theory. All I know is I had a Toyota Previa (Petrol) that stood untouched for over 3 years and when I put a new battery on it started and ran fine.

I have chain saws and Strimmers that sit unused for ages and when I go to start them they start. I have petrol lawn mowers that sit full of petrol all winter and they start in the spring.

I have 11 boats all have petrol sitting in various tanks some for long periods of time............ Quess what when I go to start them they start. Most of my engines re boats are older 2 strokes I will confess.

So you can believe those that spout theory or go on real world..... Up to you.
 
cherod said:
yes, to a certain extent and over a prolonged period , say 1 year , it will loose some of its octane , ( i believe that is correct ) , it will still run the engine but not so well.
Click to expand...

What are your real world experiences of this I wonder
 
darren west said:
The boat project I have just got has a very large aluminium tank. And the floods thing is nearly full. At a guess it’s a 200l tank.
The guy I got it from
Is a first class bu#####tter. He said it’s a year old. But so far he lied about everything so I do t believe him about anything.
But I would cry if I dumped £250 wort of petrol. Any thoughts.
Click to expand...

You have just got to try and start it. This is an issue for all of us with inboard speedboat tanks. Most of us end the season with lots of petrol in the tank. If you could dump it Most wont so just try it
 
certainly would not be dumping it ,, that is only 40 g at todays prices ,, nothing can go wrong, maybe just a little loss in performance for the weekend . diluting it will just extend the issue .
 
Bigplumbs said:
What are your real world experiences of this I wonder
Click to expand...
a car of mine sat for over a year without running ( sor , occasional start up to keep the battery charged ) because of an engine prob ,,, replacment engine was fitted and car started immediatly ( as always ) but would not tick over , mech told me to get 5 gal of 99 ron which i did and car ran perfectly , apparently it is the octane which depletes , maybe evaporates ,, ok ?
 
I find that petrol goes off even in sealed containers. Engine works but is lumpy, etc.

At the start of the season I use fresh fuel and then blend in the previous year. Normally mix about 50/50 once I have used the first 5 gallon tank of new petrol.
 
it starts to go brown like weak black tea if it is really old - like years. I had about 10 litres like that, poured it over the farm burning pile and threw a burning rag into it from 30 feet away. Went up like something from an action film. quite cool! And obviously still very combustable.
 
Yes petrol can and does go off and always has done. .

But more so these days , long since with no lead and for a while with ethanol added . These things are not good for the shelf life of petrol.

If mixed with good 2 stroke oil the oil may act as a stabiliser but it will still go off eventually .

I find last years petrol performs poorly in my lawnmower and also the same in the outboard . So I try to consume any fuel before the end of lawn mowing season and I try to leave the outboard near empty of fuel when it is put away after use.

If the engine runs rough putting some fresh fuel in may well revive it.
 
The carp that comes out the pump today goes off really quickly, the light ends and the butane that go in the witches brew that is unleaded petrol like nothing better than evaporating at room temp, sealed containers only slow that down, they don't stop it. How quickly that affects the real world use of it depends on what you're burning it in; whizzo highly tuned fuel injected things might baulk at burning what an old fashioned two stroke egg whisk will run on fine.
 
Some actual facts (remembering that I worked for BP for seven years) ...

The "shelf life" of petrol stored in a full sealed container is at least 12 months, potentially longer

If there is air in the container, or if air can get in, that could be reduced to as little as 2 to 3 months before *some* of the more volatile components evaporate off. This may, or may not, cause running and starting problems with engines but it can be worked around by topping up with fresh petrol (recommended at least a third so if you've got 30 litres, add 10 fresh)

Petrol mixed with biofuels (i.e. E5 and E10) will keep just as long provided air and, critically, water is excluded

However, if water gets into the tank, E5 and especially E10 will potentially and quite rapidly (within weeks) suffer from phase separation where the ethanol migrates out of the fuel into the water. You'll end up with something that looks rather similar to diesel with the dreaded bug i.e. a brown liquid with petrol floating on top of it.

Diesel can in theory be stored almost indefinitely as it doesn't suffer from volatiles evaporating off. However, water is once again the potential killer with the potential for developing the dreaded bug

So the best advice for fuel storage is full tanks with all vents and openings airtight
 
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