Using up petrol

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gilesfordcrush

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Hello all,

I have two regular green plastic automotive cans of petrol on my boat, for filling up my 2 stroke outboard. Neither is labelled unfortunately, but I know they were only filled towards the end of last summer. I am fairly certain that one is unadulterated unleaded, and the other has been treated with 2-stroke oil for the outboard. I would like to use up this petrol, and not leave it for a few more months until I start to use the outboard again.

I am wondering if I can add them to my 2.0 petrol Ford Mondeo? Each can is about half full - about 2.5 litres in each. Using it up in the car seems like the most environmentally responsible method of using it up. However, even if I put in a full tank of new petrol from a filling station am I risking some kind of engine problem having added 2stroke oil? Even in quite small quantities? The tank of the car is approx 60 litres. I suppose I could add it in small quantities over a few fills?

Giles
 
For £6 worth of petrol, I'd only use it in a vehicle with no cat converter or where I didn't care.

OTOH What is the mix 50:1? so we might be looking at 50cc of oil. A lot of cars burn that much oil in 100 miles with no issues.

If the cans are tightly sealed the fuel will probably be fine. I'd use it in the strimmer. Or a motorbike.

I'm pretty sure it will be fine, but for £6 I'd be cautious with a really modern car, there is just so much going on that we don't fully understand.
If your Mondeo is like my old one, anything goes so long as it's got time to get over it before the next MOT.
 
You could put it in a diesel car rather than a petrol. 5l in a tank full.

Your mix should be coloured though?

Failing that put 2 stroke oil in one can for 50:1. if your outboard smokes like a good un, tip half the fuel into an empty can. top up from your other petrol can, and vice versa?

Mike
 
Yes you should be able to spot the difference colourwise. Personally I haven't had a problem with old fuel, (its not that old) but I have had with dirty. I'd try the old mixed fuel in the outboard in a dustbin. I expect it will be fine. I used to give my old mixed fuel to a friend who drove an older car.........made sure she had half a tank to dilute it. If you are 100% dependent on the outboard and can't row you might be more risk averse.......
The other way is a gamble, refresh the old fuel with some fresh. Yes old fuel degrades but personally I'd try it first and not assume it's no good.
 
How old is the Mondeo? If it’s fairly new the engine is likely to be monitored by an array of sensors and may well pick up an affect of oil in the fuel. Would you be prepared to risk a potentially costly visit to a garage for a couple of pounds worth of old fuel? Of course, the engine emission monitoring systems may be perfectly happy but is it worth the risk?

It should be easy to tell which can has had the oil added........use the palm of your hand, let it evaporate and see if there’s an oily residue.

There are plenty of applications where it shouldn’t really matter but even these risk fouling the spark plug if they are 4-stroke, especially if the mixture is calculated at 50:1 plus a bit for luck!

The new season is only weeks away, if the cans have been air tight I’d leave well alone and use this as an excuse to use the dinghy nice and early.
 
gilesfordcrush said:
Hello all,

I have two regular green plastic automotive cans of petrol on my boat, for filling up my 2 stroke outboard. Neither is labelled unfortunately, but I know they were only filled towards the end of last summer. I am fairly certain that one is unadulterated unleaded, and the other has been treated with 2-stroke oil for the outboard. I would like to use up this petrol, and not leave it for a few more months until I start to use the outboard again.

I am wondering if I can add them to my 2.0 petrol Ford Mondeo? Each can is about half full - about 2.5 litres in each. Using it up in the car seems like the most environmentally responsible method of using it up. However, even if I put in a full tank of new petrol from a filling station am I risking some kind of engine problem having added 2stroke oil? Even in quite small quantities? The tank of the car is approx 60 litres. I suppose I could add it in small quantities over a few fills?

Giles
Click to expand...

Part full plastic cans is just about the worst way of storing petrol.

If I were you I would determine which has oil added and which doesn't by allowing a little of each to evaporate from a shallow dish or saucer to see which leaves an oily residue.

Put the fuel that does not contain any oil in the car.

Filter the other if possible and add an equal volume of fresh 50: 1 two stroke mixture. Use that for your outboard
 
Pour them into one can and add more oil (half the normal quantity added to 5L) and you have a full can of 2 stroke.

P.S. Fuel in sealed can will last for a year or more. Outboard petrol usually goes stale because the tank is only part full and the vent is not closed.
 
Last edited:
ibbo said:
You could put it in a diesel car rather than a petrol. 5l in a tank full.

Mike
Click to expand...

Ouch! Some modern diesels cant take even a small amount of petrol. You can wreck the entire injection system! The petrol attacks the seals, and even if it doesnt show up straight away, there's trouble brewing a bit further down the road.

Old style diesels didnt give a toss. My 1995 Renault diesel once ran quite happily several hundred miles on 35% petrol after a moments inattention at the pumps and deadline to make. A bit of power loss, but otherwise not a murmer, but a colleague misfuelled his new diesel Merc with only a few litres of petrol, and did over £7k of damage.
 
As oldharry has said. Never put petrol in a modern diesel engined car !!! The ultra high pressure pumps and injectors used to increase power and reduce emissions in these latest diesel cars would be ruined in a moment with petrol.
The 2.5 lts of mix at 50 to 1 mixed into 60 lts in the Mondeo tank is so infintesimal, it will have no effect .

No doubt someone of mathematical learning may come up with a figure.
 
I had running trouble with a Suzuki 2-stroke outboard with year-old fuel, cured with fresh, so I think the lawnmower is the best suggestion. You could try my late MIl's method of using it to light a bonfire, but then again better not. She did survive though.
 
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