What happens if 2 stroke mix is wrong

Owning an outboard that requires a 50:1 mix I was carefully mixing the oil in in advance of needing it at the weekend.

Like an idiot I mixed at 25:1. Fortunately the ob is full of 50:1 - it's just the 5l petrol can that is wrong.

I only have 1 petrol can here, full to the brim. And I filled the car up at the same time to the brim so can't dispose of a couple of litres there.

The only option I can think of is to go and buy another petrol can, share the 25:1 equally between the two and then refill the two cans with fresh petrol to dilute to 50:1

However, I don't use much petrol, a single 5 litre spare can is all I really need so if I do this I'm then left with a can I don't really need.

Alternative is to burn 2.5 litres in the car, top up from the two stroke and them refill but not sure that I'd be able to accurately dispose of 1/2 the premixed and not too keen on getting rid of old 2 strike in the car unless I have to.

Anyone got any bright ideas???

Just use it at 25:1 may smoke a bit but won't hurt. I forgot to add some oil last year on a refill so next I ran it on 25:1 for half a tank just to get the bearings well oiled up again.

Owning an outboard that requires a 50:1 mix I was carefully mixing the oil in in advance of needing it at the weekend.

Like an idiot I mixed at 25:1. Fortunately the ob is full of 50:1 - it's just the 5l petrol can that is wrong.

I only have 1 petrol can here, full to the brim. And I filled the car up at the same time to the brim so can't dispose of a couple of litres there.

The only option I can think of is to go and buy another petrol can, share the 25:1 equally between the two and then refill the two cans with fresh petrol to dilute to 50:1

However, I don't use much petrol, a single 5 litre spare can is all I really need so if I do this I'm then left with a can I don't really need.

Alternative is to burn 2.5 litres in the car, top up from the two stroke and them refill but not sure that I'd be able to accurately dispose of 1/2 the premixed and not too keen on getting rid of old 2 strike in the car unless I have to.

Anyone got any bright ideas???

Give it so someone with a Seagull that runs on 25 :1

Lawnmower or other garden machinery.

Wife's car

Dont worry about using exactly half and topping up. Aim to use a bit less than half so that your resulting mix is a bit more oily than 50:1, rather than less oily.

Just use it any way as it is . Your outboard would have used 25:1 during the break-in period

The OB will run fine on it.

Just enjoy the angst of knowing you are polluting the environment a little more than usual.

Sounds like the kind of question I got in Maths A Level, ( 36 years ago! ).

Is it me?

Give half the fuel to a Seagull owner and top up the tank with petrol.

Running a gallon of slightly over oiled fuel through it will do pretty much no harm at all if it's modern oil designed for outboards; it might smoke a bit more and possibly struggle to idle if the plug is elderly, but more than that is unlikely. I'm slightly alarmed at the folk who would feed it to modern cars with catalytic converters; the oil could well shorten the converter's working life. Grotty old pre-catalyst bangers perhaps, but not anything newer.

. I'm slightly alarmed at the folk who would feed it to modern cars with catalytic converters; the oil could well shorten the converter's working life.

The possible effects , if any, of burning a small quantity of 2stroke outboard engine oil in a vehicle fitted with a "cat" has been raised before.

Its ashless so difficult to see that there will be anything to contaminate a cat but you presumably know something about this. What does a TCW3 oil contain that will damage a cat. How much would be needed to cause any damage.

.

The amount would likely cause little or no damage, I was trying(and failing now I reread my post) to get across that the car is more likely to be harmed by the fuel than the O/B.

The amount would likely cause little or no damage, I was trying(and failing now I reread my post) to get across that the car is more likely to be harmed by the fuel than the O/B.

Yes i understand that but what is there in a tcw3 oil that would harm the car.

I suspect it contains nothing that will contaminate a catalytic converter.

I've been disposing of the odd gallon or two of old two stroke mix in the car at the end of every season. Car's done 130K now, still on the original cat, and well in limits at last months MOT.

My Mercury seems pretty tollerant on strict oild / fuel ratio too - l'd say just try it

Yes i understand that but what is there in a tcw3 oil that would harm the car.

I suspect it contains nothing that will contaminate a catalytic converter.

Don't know but I understand from my local garage that they have to be very careful about any gasket goo etc used upstream from a cat. as old traditional materials could poison it so it sounds as if they're sensitive. Also the wholesale adoption of fuel injection with lamda sensors etc. in the early 90's was to permit the use of cats. - carbs. couldn't deliver a sufficiently accurate mixture.

Just use it any way as it is . Your outboard would have used 25:1 during the break-in period

+1
And I thing that commercial users of two-strokes (ie heavy and long hours) are supposed to run them on more oil to increase lifespan.

... this has the very distinct advantage that it does not go 'off'.

I use Briggs & Stratton Fuel Fit Additive/Stabiliser even with 2T fuel: http://amzn.to/1jpCxR5

In addition, the empty measuring bottles are handy for dispensing diesel bug additive, in my case Grotamar: http://amzn.to/1h7JLbh

It won't bother the cat on a car! Mrs Avocet's last car (which had a cat) used to drink engine oil. FAR more than we're talking about here! Even the handbook said that up to 1000km per LITRE of engine oil was not excessive. Cat (and lambda sensors) were still fine when we sold it at 80=odd thousand miles.

Running a gallon of slightly over oiled fuel through it will do pretty much no harm at all if it's modern oil designed for outboards; it might smoke a bit more and possibly struggle to idle if the plug is elderly, but more than that is unlikely. I'm slightly alarmed at the folk who would feed it to modern cars with catalytic converters; the oil could well shorten the converter's working life. Grotty old pre-catalyst bangers perhaps, but not anything newer.

5 litres of 25:1 is 200ml of oil.
My wife's car burns that from its own sump in 1000 miles anyway. It's ten years old and still on its original cat.
Personally I would buy another fuel can, it's not much dearer than buying another spark plug.
I tend to keep on fuel can of 'clean fuel' and one of mixed. That way I can buy 5 litres in good time before running out of mixed.