Does Petrol go 'off'

Scoobysnax · 21 June 2009, 10:38

I have 20-30 litres of unleaded petrol stored in appropriate canisters for the last 9 months.
Does petrol go off - can it be used without problems?

Nos4r2 · 21 June 2009, 11:15

Quote:

Originally Posted by Scoobysnax

I have 20-30 litres of unleaded petrol stored in appropriate canisters for the last 9 months.
Does petrol go off - can it be used without problems?

Yes, it does go off but if it smells exactly like fresh petrol it'll be ok.

Hightower · 21 June 2009, 11:27

9 months is old for petrol. However I have used old petrol mixed with new so that none is wasted. Not too sure if you should do this, but I added it to my car's tank at about a gallon per tankful. didn't seem to affect the running. Make sure there's no water contamination.

Bigmuz7 · 21 June 2009, 13:10

I always run my inboard tank to almost empty before winter storage, however I keep a separate aux tank, and at the first outing of the season, I put it into the main tank, then top up the main tank with fresh, and refill the aux tank with fresh, so the main tank has old but dilute old in it ,... and this seems to work ok. Id probably prefer to use the old stuff from the aux tank in a lawnmower or something, but I dont have that much grass

Paul L · 21 June 2009, 14:02

Apparently old stagnant petrol crystalizes but someone once told me to give it a good shake and it would be ok.I've done this for the last three years following the winter and never had a problem yet.Following on from that,at the start of the new season i fill my tanks with new petrol so maybe diluting it helps.

codprawn · 21 June 2009, 14:39

What happens is that the aromatics like benzene and toluene evaporate. If you store petrol in a sealed tank with no breathers and make sure the tank is full with no air gap you will be fine.

If the fuel has degraded a bit you could mix it 50/50 with super unleaded or chuck some toluene in it!!!

slimtim · 21 June 2009, 14:40

I used my rib at the end of summer 2007, went to canada for a year and then used it for the first time at the beginning of may and it ran fine with 3/4 of a tank of old petrol and 1/4 new. That was until the starter motor packed up and left me drifting off black rock

Avocet · 21 June 2009, 16:41

As agreed above, petrol does indeed deterioriate.

The problem is, however, twofold: firstly the volatiles can evaporate and secondly sticky deposits form which can block injectors, carburettors and even pipes. The first happens quite soon (after a couple of months) but can be overcome by dilution (as mentioned above). The deposits take longer (several months) to form and can usually (but not always) be overcome by efficient fuel filters (although in extreme cases the filters themselves may block).

The damage that the deposits can cause, however, means that you should be very careful about using old fuel in equipment that is expensive or where failure may result in a safety issue (eg marine engines at sea).

BrAinZ · 21 June 2009, 22:54

Petrol definitely goes off. If I am leaving fuel in my boat for any length of time, I add Fuel Stabaliser to help keep it fresh and stop any sludge forming.

Can't remember the exact brand, but just do a Froogle search, or you should be able to buy it from a local Chandler.

Bigmuz7 · 21 June 2009, 23:09

Quote:

Originally Posted by BrAinZ

Petrol definitely goes off. If I am leaving fuel in my boat for any length of time, I add Fuel Stabaliser to help keep it fresh and stop any sludge forming.

I'm wary of that stuff .. I dont have proof .. but rekon it killed an injector in an optimax engine I had, resulting in it shutting down to guardian mode for an uncomfortably long trip .. dont know if its suitable for all engines

Scoobysnax · 21 June 2009, 23:40

Thanks for the above.
For the sake of a few quid methinks it makes sense to dispose of the fuel

codprawn · 22 June 2009, 01:45

If you have a diesel landrover chuck it in with a bit of cooking oil - it's what I do!!!

Jon.esp · 22 June 2009, 12:15

I leave my boat stored ashore in a shed in Spain. Over the winter months this can be for 5 or even 6 months whilst it may be 6 or 8 weekly intervals in the summer. When in use it may do 5 or 6 hrs a day everyday.

When I store it I usually try to brim the 170l tank to stop any condensation although if I expect to be back in the next month or so I don’t bother. 170L of fuel is a lot of €s tied up so in a way I would rather leave it MT.

So full tank and fuel goes stale or empty tank and I pick up condensation in the tank and so water in fuel.

What in your opinion is potentially the worse of the 2 evils? I had instinctively thought water in fuel but perhaps I am behind the times.

Perhaps I should say I do use the Quicksilver fuel conditioner as a mater of course and have always assumed for an Optimax that would be OK. I haven’t noticed any residue build up in the filter but it may be in the fuel lines and I haven’t spotted it.

Jon

chewy · 22 June 2009, 12:38

Can't you just put some octane booster in. Thats all I do if I'm in any doubt about the fuel.

PeterM · 22 June 2009, 13:44

Quote:

Originally Posted by Bigmuz7

I'm wary of that stuff .. I dont have proof .. but rekon it killed an injector in an optimax engine I had, resulting in it shutting down to guardian mode for an uncomfortably long trip .. dont know if its suitable for all engines

I am scewed then - I wait for the injectors to pack up ! ooops !

BrAinZ · 22 June 2009, 17:58

I love the Internet, but isn't it funny how everyone always has different opinions on exactly what's the "best" thing to do

we need a fuel expert to give us a definitive answer

Rigaud · 22 June 2009, 18:37

Gasoline is best kept out of sunlite and open air also kept in cool places to remain fresh but from the moment it is made the life of gasoline is aprox. 2000hrs (3 months). Afterwards it starts to loose its octane value if left sitting for too long a period of time. left sitting over the winter in the engines, well vanish like deposits accumulate. Those varnish deposits is the #1 cause of engines not starting come spring time or performing badly.

In most basic engines using old gas will work unless its years old but for high performance engines and especially with high compression you could burn out the motor.

And using stabilizers can work for a while but only if added when the gas has been just purchased. Trying to use stabilizer after 3-6 months is a waiste of time.

Cheers

Bigmuz7 · 22 June 2009, 19:02

Quote:

Originally Posted by Blackroady

I am scewed then - I wait for the injectors to pack up ! ooops !

Well it was evident on the first run out after winter storage after the conditioners use, If you've had a blast already this season, and you are running on fresh juice now, you should be ok .. dunno whats in the stuff .. it doesnt even smell that aromatic

Quote:

Originally Posted by Jon.esp

So full tank and fuel goes stale or empty tank and I pick up condensation in the tank and so water in fuel.

I have a plastic inboard tank fitted with a breather that lies at ambient temperature, for 6 months during the winter, with a small amount of fuel in it, and I have yet to see a drop of water in my fuel, and I check the filters fastidiously

And its not because the outlet sits off the tank bottom either because I have a fuel extraction scheme for supplying the aux if the aux tank runs out, which is a suction hose into the tank bottom and I check the output from that too with no problems thus far

GerryP · 22 June 2009, 22:40

Quote:

Originally Posted by Scoobysnax

Thanks for the above.
For the sake of a few quid methinks it makes sense to dispose of the fuel

.
How/where do you dispose of old fuel?
Too much to save until bonfire night, both my cars are diesel not petrol, lawnmower doesn't use that much, etc...
With local councils being tighter and tighter on what you can dispose of where do you dispose of old fuel??
.
Great thread re things to try with old fuel if you want to keep it, but at £15.00 for 1/2 a tank full, may not be worth the cost to try and save the petrol vs other costs and engine running issues(?). Agree with scoobysnax.

codprawn · 22 June 2009, 22:49

Quote:

Originally Posted by GerryP

.
How/where do you dispose of old fuel?
Too much to save until bonfire night, both my cars are diesel not petrol, lawnmower doesn't use that much, etc...
With local councils being tighter and tighter on what you can dispose of where do you dispose of old fuel??
.
Great thread re things to try with old fuel if you want to keep it, but at £15.00 for 1/2 a tank full, may not be worth the cost to try and save the petrol vs other costs and engine running issues(?). Agree with scoobysnax.

If your cars are older diesels then just chuck it in the tank. A few litres into a full tank now and again won't hurt and actually helps in the winter. To be safe chcuk in a litre or 2 of cooking oil as well - and yes I AM serious!!!

I often get free fuel from a mates garage this way cos most people are too scared to use mixed fuels.