Does Petrol go 'off'

[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?

[Nos4r2]

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]

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]

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]

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]

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]

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]

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]

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]

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