2 stroke petrol/oil mix

[rogerthebodger]

Thank you guys for your help.

Yes there will be a question as ti if the petrol has gone off as this is in Richards Bay where yesterday the temp was 32 C at 10 AM on the way home it reached 34 C at about 1500 m above sea level.

It looks like I will try the everapation test, if that fails just add some more 2T oil.

Thanks again.

 

[pvb]

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.

It rarely gets up to 30degC in the UK in winter. My Stihl chainsaw starts virtually first time on the existing fuel in its tank, even after being left in the garage for 6 months or more. I top it up with premixed fuel which can easily be 2 years old, as I said, and don't have any difficulties. Maybe Stihl engines are better designed than the average outboard.

 

[VicS]

It rarely gets up to 30degC in the UK in winter. My Stihl chainsaw starts virtually first time on the existing fuel in its tank, even after being left in the garage for 6 months or more. I top it up with premixed fuel which can easily be 2 years old, as I said, and don't have any difficulties. Maybe Stihl engines are better designed than the average outboard.

Maybe but engines vary in the way they react to old petrol.
My old petrol Flymo will never start on the previous years fuel.

The Seagulls start but don't run well on old fuel, They are Ok on 1 year old stuff, which is what they usually get, but don't like it if is 2 years old

I have never tried old fuel on its own in the Evinrude. I always store fuel over winter in full, tightly capped metal cans, filter if before use and mix 50:50 with fresh

My chain saw only runs when fed with 240 volts

 

[Lon nan Gruagach]

It'll taste different.

 

[rogerthebodger]

It'll taste different.

No Thanks.

 

[coveman]

I was told by a Yamaha dealer that even if a 2 stroke engine has a recommendation for 100:1 in the handbook, it is advisable as the engine ages ( and most will be relatively old now in the UK) to use a 50:1 mix. His reasoning was that most engines of this age will have significant wear.

 

[colind3782]

Try a blotter test? Put a sample of the mix onto blotting paper (coffee filter will do) and leave it to dry for several hours. The two components should separate showing distinct "rings". Several decades since I've done this so the details may be sketchy but the principal should work.

 

[lw395]

Maybe but engines vary in the way they react to old petrol.
My old petrol Flymo will never start on the previous years fuel.

The Seagulls start but don't run well on old fuel, They are Ok on 1 year old stuff, which is what they usually get, but don't like it if is 2 years old

I have never tried old fuel on its own in the Evinrude. I always store fuel over winter in full, tightly capped metal cans, filter if before use and mix 50:50 with fresh

My chain saw only runs when fed with 240 volts

These days, if something won't start, fresh petrol is fairly well up the list of things to try.
I've got a cheap chinese strimmer/pruning saw, I've taken to emptying its tank back into a sealed can after use, unless I'm going to use it in the next few days. Likewise my 2HP outboard is stored empty of fuel.
240V mower and Li-Ion hedge trimmer have saved a lot of mucking about.
My bike always seems to run better after a couple of tanks of new fuel in the Spring.

 

[jdc]

Try a blotter test? Put a sample of the mix onto blotting paper (coffee filter will do) and leave it to dry for several hours. The two components should separate showing distinct "rings". Several decades since I've done this so the details may be sketchy but the principal should work.

I'd definitely try this test. I think that the separation of the hydrocarbons in the petrol and oil will probably not be that evident, but I'd hope that the die in the 2-stroke oil would end up as a visible band. I'm just going to the garage to try it out!

EDIT: Ok I tried the chromatography. I'm sad to say it didn't work at all. This may be because the motility of the petrol is so high in the media ('blotting paper') I had available. But what did work, really well and really quickly was putting 5cm3 or so in a desert spoon and rolling it around for 2 or 3 mins. I did it with pure petrol and with 50:1 2 stroke. Both evaporated surprisingly fast (it's about 10 deg C here) but the spoon with pure petrol stayed clean whereas the one with 2% oil soon got 'legs' rather like fine wine or jam just about to set.

 

[thinwater]

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.

Stored in a tight can it is fine. However, it is true that 2-stroke oil absorbs more water from they air and that this accelerates corrosion. I've done the lab testing. The difference is so small it is basically triva, but that is how these things get started. That said, I never mix more than a gallon ahead. No reason.

 

[QBhoy]

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

What mercury is that ? I can’t think of a mercury that runs 100-1.

 

[Old Harry]

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.

I was comparing 40 deg to 4 deg 2 t storage / use

 

[Old Harry]

What mercury is that ? I can’t think of a mercury that runs 100-1.

100 : 1 was a marketing gimmick

 

[QBhoy]

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

100 : 1 was a marketing gimmick

Never heard of it on a Merc. Aware on a Yamaha. I’ve a few old Yamaha but always mix at 50-1 with them.

 

[coopec]

It rarely gets up to 30degC in the UK in winter. My Stihl chainsaw starts virtually first time on the existing fuel in its tank, even after being left in the garage for 6 months or more. I top it up with premixed fuel which can easily be 2 years old, as I said, and don't have any difficulties. Maybe Stihl engines are better designed than the average outboard.

But Roger (the originator of the thread) lives in Johannesburg (SA) where the temperature would often be in the 30s

 

[pvb]

But Roger (the originator of the thread) lives in Johannesburg (SA) where the temperature would often be in the 30s

What happened to your sense of humour?

 

[rogerthebodger]

What happened to your sense of humour?

Sometimes your comments can be a bit offensive so its difficult to till when you are joking.

The boat and fuel are in Richards Bay. Last week the temperatures were well over 30 C so Clive is very correct.

I was interested in the comments by lw395 and others about diesel stored in temperatures over 30 C as inside my sailboat the temperature are very often over 30 C

 

[ghostlymoron]

The HASAWA legislation only applies at work. You can be as crazy as you like in your leisure activities.

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