2 stroke petrol/oil mix

[rogerthebodger]

I have a couple of cans of petrol for my outboard mobo and I cannot remember if I added the 2 stroke oil into the petrol when I purchased the petrol.

Any simple test I can use to determine if I did add the 2 stroke oil or not.

Cannot use the petrol in my car as the car I use at the coast is only diesel.

 

[fredrussell]

Can’t you tell by the colour of it? 2T oil is usually coloured. Straight petrol is the colour of white wine.

 

[pvb]

Just add some more oil; if it ends up 50:1 rather than 100:1 (for example) it won't make any real difference to performance.

 

[black mercury]

Just add some more oil; if it ends up 50:1 rather than 100:1 (for example) it won't make any real difference to performance.

+1 My mercury runs happily on 50:1 even though it's supposed to be 100:1, so adding more oil will be fine.

 

[RichardS]

It depends on how quickly you want an answer.

If you pour even as little as 25 mls into a beaker and leave it to evaporate for a few days, you will see/feel a thin film of oil in the bottom. If it's petrol, there will be nothing visible/feelable at all.

You could speed things up by applying heat.

Richard

 

[lw395]

Leave some to evaporate.
A teaspoonful of petroil should leave something feeling oily, straight petrol will be clean or sticky?

Normally the red or green colour is pretty obvious, but I have had straw-coloured 2T oil in the distant past.
50:1 will be OK in a 100:1 engine, but I usually use 66:1 or 50:1 where 100:1 is called for, so a double dose would be 25:1, which is getting into plug-oiling territory if you do any slow running.

 

[anoccasionalyachtsman]

I had the same problem in summer, and did the evaporation thing as above, but on some white kitchen roll. That left a brown trace which.......I can't work out how to finish this senten S'pose I'd used loo roll?

I had put oil in.

 

[CLB]

If the mix is already 50:1 then doubling it will cause problems. Most 100:1 engines are really 50:1 engines anyway, so if you normally mix 100:1 then doubling will in fact be better for the engine.

Having said that, I agree with the colour test. Pour some into a glass. it shoudl be obviously red/blue (depending upon the colour of your oil) if it already has some in.

 

[Spirit (of Glenans)]

Two comments:
1. Be careful what kind of heat you apply to your sample!!
2. AFAIK the received wisdom regarding the addition of 2T is that it's better done just before it's needed, as it goes off.

 

[pvb]

2. AFAIK the received wisdom regarding the addition of 2T is that it's better done just before it's needed, as it goes off.

The 2-stroke oil goes off? How? I have mixed fuel in my garage which must be 2 years old, and it still works fine in my chainsaw.

 

[Old Harry]

The 2-stroke oil goes off? How? I have mixed fuel in my garage which must be 2 years old, and it still works fine in my chainsaw.

we dont seem to have a popcorn smiley :sleeping:

 

[pagoda]

The 2-stroke oil goes off? How? I have mixed fuel in my garage which must be 2 years old, and it still works fine in my chainsaw.

Petrol of almost any breed goes off if it's not used. It gums up carburetors and fuel valves. Our 2T outboard is never happy with old petrol, so it gets replaced each season. I don't appreciate unplanned rowing in filthy weather!

 

[coopec]

The 2-stroke oil goes off? How? I have mixed fuel in my garage which must be 2 years old, and it still works fine in my chainsaw.

I used to work for an oil company and I am aware petrol has a limited life. My understanding is that the volatile parts of the petrol separate (could be wrong)

Using a different brand of 2-Stroke oil? Petrol has limited shelf life (as low as 30 days), so always mix with fresh regular unleaded, purchased from a reputable large volume fuel supplier. To prolong the life of your 2 Stroke fuel mix you can add STIHL fuel stabiliser to extend the fuel's shelf life up to 12 months.
https://www.stihl.com.au/mixing-2-stroke-fuel.aspx

The storage life of petrol is one year when stored under shelter in a sealed container. Once a seal is broken the fuel has a storage life of six months at 20°C or three months at 30°C. The storage life of petrol in equipment fuel tanks is one month.

https://www.bp.com/content/dam/bp-c.../opal-fuel/Opal-factsheet-storagehandling.pdf

 

[Old Harry]

I used to work for an oil company and I am aware petrol has a limited life. My understanding is that the volatile parts of the petrol separate (could be wrong)

Using a different brand of 2-Stroke oil? Petrol has limited shelf life (as low as 30 days), so always mix with fresh regular unleaded, purchased from a reputable large volume fuel supplier. To prolong the life of your 2 Stroke fuel mix you can add STIHL fuel stabiliser to extend the fuel's shelf life up to 12 months.
https://www.stihl.com.au/mixing-2-stroke-fuel.aspx

The storage life of petrol is one year when stored under shelter in a sealed container. Once a seal is broken the fuel has a storage life of six months at 20°C or three months at 30°C. The storage life of petrol in equipment fuel tanks is one month.

https://www.bp.com/content/dam/bp-c.../opal-fuel/Opal-factsheet-storagehandling.pdf

Its under 5 deg here now

 

[coopec]

we dont seem to have a popcorn smiley :sleeping:

+1

 

[coopec]

Its under 5 deg here now

Well it's going to be 42 deg here today with a 40 kph easterly wind.

(Not planning to work on the yacht today)

 

[coopec]

Its under 5 deg here now

I am bemused when you guys talk about different types of heaters for your boats

I couldn't be bothered with boating/yachting when it is freezing cold. As they say that would be like standing in a cold shower ripping up hundred dollar notes.

 

[VicS]

The 2-stroke oil goes off? How? I have mixed fuel in my garage which must be 2 years old, and it still works fine in my chainsaw.

I have certainly had some "go off" I admit it was somewhat older than 2 years and it was a relatively small quantity left in the bottle.

I can only describe it as going "gloopy" and not mixing with the petrol. It took an age to filter the mixture in order to recover the petrol.

 

[coopec]

Its under 5 deg here now

I believe you!!

https://www.ventusky.com/?p=53.3;-2.0;5&l=temperature-2m

 

[Skylark]

I’ve been in the same situation as the OP several times over the years but never in these times of having HS&E police spying our every activity so I’m not advocating my solution.

Simply shake the container with the lid removed and the palm of your hand over the opening.

The very small amount of fuel on your palm will evaporate almost instantly. You’ll easily tell if your palm has a residual layer of oil. Simples