Disposing of old two stroke petrol mixture ?

VicS said:
Always learning something new. I thought that "gas" was short for "gasoline"
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Gasoline because it turns to gas, duh!
Another little snippet for you, on long runs in the raw gas pipes from the gas oil separators I worked on in Africa and the Middle East if there was a dip or a low point in the pipe we would put in a drain valve where the operators would drain off the condensate. They would use it in their lo compression "pick me ups" They called it "drip gas" Most of the operators were from Texas, Oklahoma or Louisiana, they explained it was one of the perks of the job back home. The Angolans particularly valued it, it worked fine in their Suzuki 50cc motorcycles.
S
 
RichardS said:
There are several different strands of thought here.

FWIW this is my summary.

Any fuel, petrol, two-stroke or diesel, in an airtight container will not "go off" unless you are talking about years of storage at warmer temperatures or exposure to sunlight when, I accept, it might be possible for some side-reactions to occur. Talk about lighter fractions is irrelevant ..... the container is airtight.

Fuel stored in a vehicle depends upon how airtight the system is. If it is fuel injected any evaporation of light fractions is likely to be minimal and result only from evaporation through the main tank breather. This is likely to be very limited, especially if your vehicle does not smell of fuel when standing still. The engine will run fine as there is not a small reserve in a carburettor to be affected.

In a carburettor engine, there may be evaporation through the jets and intake manifold. This will be worse with two stroke mixture which will become over-rich. Different engines will be differently affected depending upon jet size and natural ambient airflow through the manifold. Even in an engine which has high evaporation, which you might be able to smell just standing next to the motor, it is only the small amount of fuel in the carb which might be affected. Just drain that 50cc off and add it back to the main tank. Problem solved.

Some engines have minimal ambient airflow through the intake manifold. The fuel in these carbs will not go off. :encouragement:

Richard
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lighter fractions are relevant. Today I took the plastic ob petrol tank out of the locker and left it on the sugar scoop. It is 30 deg C today in Albufeira. The plastic tank swelled up. I unscrewed the cap, psshhh went the light ends as they escaped. I know that this will happen several times over the next few weeks as I use up the fuel. So, take heed of someone who worked in the oil industry for most of his life, who also takes note of what happens in real life as well.
S
 
skipper_stu said:
lighter fractions are relevant. Today I took the plastic ob petrol tank out of the locker and left it on the sugar scoop. It is 30 deg C today in Albufeira. The plastic tank swelled up. I unscrewed the cap, psshhh went the light ends as they escaped. I know that this will happen several times over the next few weeks as I use up the fuel. So, take heed of someone who worked in the oil industry for most of his life, who also takes note of what happens in real life as well.
S
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Did you even read my post? I covered raised temperatures, sunlight and airtight containers.

The situation you describe is nothing to do with fuel going off during storage. If you put any airtight container of petrol in direct sunlight at 30 degrees for even a short period and then make it non-airtight by releasing the pressure you will lose vapour which will contain a high proportion of light fractions.

If you had left the tank to cool back down to its original temperature the light fractions would have been re-absorbed and nothing would have been lost.

You don't need any experience in the oil industry to understand this chain of events.

Richard
 
I had a car parked in the garage, unused, for eight years, with the tank about 1/4 full. After putting a new battery in, it started first turn of the key, and ran without problems.
So I take the "petrol going off" with a bit of a pinch of salt.
 
Thanks for all the replies. I really did not think such a mundane question would spark such a flurry of contrary replies ! I still don't know where one may recycle old fuel! As my Landrover runs on diesel and Mrs Bergamot's little Fiat 500 has a catalytic converter and I don't want to mess it up, I think I will use my old 2 stroke in my strimmer and chainsaw and dilute it into my 4 stroke mower over the summer. It may take me a while to use it but at least it will get used. Thanks again.
 
Bergamot said:
Thanks for all the replies. I really did not think such a mundane question would spark such a flurry of contrary replies ! I still don't know where one may recycle old fuel! As my Landrover runs on diesel and Mrs Bergamot's little Fiat 500 has a catalytic converter and I don't want to mess it up, I think I will use my old 2 stroke in my strimmer and chainsaw and dilute it into my 4 stroke mower over the summer. It may take me a while to use it but at least it will get used. Thanks again.
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If you still have any left come the winter, blend it in with the diesel in the Land Rover for better starting on cold mornings. Quite common to put a bit of petrol in the diesel in places where it gets seriously cold. The bit of two stroke oil in there will do the lubrication of the fuel system no harm.
 
I tipped last year's left over 2T mix into my boat's diesel tank. I reckoned the engine wouldn't notice the 4 liters of petrol as it was being diluted by 150 liters of diesel.
 
michael_w said:
I tipped last year's left over 2T mix into my boat's diesel tank. I reckoned the engine wouldn't notice the 4 liters of petrol as it was being diluted by 150 liters of diesel.
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The only objection that I am aware of is the safety aspect of having the diesel fuel system contaminated with highly flammable petroleum spirit.
 
VicMallows said:
Didn't vandals put salt into car fuel tanks back in the 60s? .... or was it sugar?

Whichever, I still have no idea if/why either of them might have worked. (to stop the engine)
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It was sugar.
I've seen the aftermath of this in a bike a friend bought as a non-runner.
Thick, toffee-like gunge in the carb, fuel tank, fuel tap etc etc.
It took us a while to twig, at first we'd thought it was a tank sealant like Petseal.
 
I too have never experienced problems with old petrol. However, this thread has made me conduct an experiment on my 4 stroke lawnmower that hasn't been used for at least 3 years. The tank was half full, gave it a good few pulls...nothing. Took out the plug, it was wet with petrol, cleaned it then pulled again with the plug removed showing a healthy spark. Plug replaced then tried again. It wanted to start but didn't. I drained the old petrol, flushed with new fuel. It started on the third pull, so let it warm up a bit. I then drained the tank and carb replacing with the old fuel. Second pull it started. I let it cool for a few hours while I was working on other stuff. It started first pull with the old fuel.
 
bikerbill said:
I too have never experienced problems with old petrol. However, this thread has made me conduct an experiment on my 4 stroke lawnmower that hasn't been used for at least 3 years. The tank was half full, gave it a good few pulls...nothing. Took out the plug, it was wet with petrol, cleaned it then pulled again with the plug removed showing a healthy spark. Plug replaced then tried again. It wanted to start but didn't. I drained the old petrol, flushed with new fuel. It started on the third pull, so let it warm up a bit. I then drained the tank and carb replacing with the old fuel. Second pull it started. I let it cool for a few hours while I was working on other stuff. It started first pull with the old fuel.
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Great stuff BB. Just one question ..... have you got too much time on your hands :encouragement:

Richard
 
RichardS said:
Great stuff BB. Just one question ..... have you got too much time on your hands :encouragement:

Richard
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I'm on holiday for Easter, I should be cracking on with work on the new house, painting ect, but footering about with engines is better fun.
 
lpdsn said:
If you still have any left come the winter, blend it in with the diesel in the Land Rover for better starting on cold mornings. Quite common to put a bit of petrol in the diesel in places where it gets seriously cold. The bit of two stroke oil in there will do the lubrication of the fuel system no harm.
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+1 for the diesel tank. Petrol can be used mixed with diesel, it was/is used to prevent waxing for summer grade diesel that was left over in storage tanks when the winter came. Parafin was also used but technically illegal because there is no duty on it, but I would not be bothered about that issue.
I don't really want to get into the bun fight of, does it or does it not go off. I always use old fuel and most times it's fine, odd times I've had poor running and I have replaced the fuel and it's sorted the problem. Six of one and half a dozen of the other me thinks.
 
Here is the exact wording from the official Honda Carburetion manual
Fuel Freshness
Engine performance is directly related to the quality and freshness of the fuel consumed. Therefore, it is important to be sure the fuel is usable for your test procedures. You may save valuable troubleshooting time by replacing fuel if its quality or freshness is in doubt.
Fuel in the fuel tank should be no more than six to eight weeks old. When using a portable fuel tank, fuel life can be prolonged substantially if the fuel vent is CLOSED after each use.
Fuel in the carburetors oxideses quickly because the fuel chambers are open to the atmosphere and this fuel can easily start to varnish in four to five weeks. This is especially true during high ambient temperatures.
 
bikerbill said:
I too have never experienced problems with old petrol. However, this thread has made me conduct an experiment on my 4 stroke lawnmower that hasn't been used for at least 3 years. The tank was half full, gave it a good few pulls...nothing. Took out the plug, it was wet with petrol, cleaned it then pulled again with the plug removed showing a healthy spark. Plug replaced then tried again. It wanted to start but didn't. I drained the old petrol, flushed with new fuel. It started on the third pull, so let it warm up a bit. I then drained the tank and carb replacing with the old fuel. Second pull it started. I let it cool for a few hours while I was working on other stuff. It started first pull with the old fuel.
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I bet if you taken the plug out, cleaned & gapped it, then put it in the oven for 15 minutes on 'quite hot' and then put it back in the mower, it would have fired straight away. I've had to resort to that with old plugs on a sunday when I couldn't get a new one. Oddly enough they were usually fine after that but I'd buy a new plug anyway.

Tim
 
I have a couple of ProShark 100cc quads 2 stroke and they are VERY sensitive to old fuel.....i foolishly mixed up a large amount of fuel so that it was 'ready to roll' for the kids and they never used it and after a few months they won't even start let alone run properly and the fuel I've mixed up is better off in a car (CL500/CLK320) than in anything else. I've got a a 25yo Kawasaki strimmer (2stroke) and that will start second pull no matter how long its been left as does a Stihl chainsaw and a Shtil hedgecutter. I can't believe its down to the build quality of the engine as they should all be of the same quality but its what works for you...... my Honda generator (for the house) (which SHOULD be the epitamy of reliability) seems to need a new spark plug every 6 months irrespective of whether its been used or not which goes against the grain of the fact that its there to be forgotten about until needed unfortunately.
 
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