steve66
Well-Known Member
Im not telling you a word of a lie, admittedly there was only a cup full of fuel in the tank but was just using the story as an example
Disposing of old two stroke petrol mixture ?
- Thread starter Bergamot
- Start date
Im not telling you a word of a lie, admittedly there was only a cup full of fuel in the tank but was just using the story as an example
RichardS
N/A
My convertible car and both my lawnmowers sit from November to March every year with the same tank of fuel and both start first go in the Spring.
Two stroke is different obviously as the petrol can evaporate and the mixture could get too oily and foul the plug. Just add it to a larger batch with the correct ratio.
Richard
FulmarJeddo
Well-Known Member
Petrol does degrade over the winter. Different engines seem to react differently to it. I have an old (late 1990s) 2 stroke 2.3hp Johnson outboard for my tender that is always difficult to start at the beginning of the season. I usually persevere and use the fuel in the tank. When I buy new petrol it miraculously improves. I also have a 2stroke 40hp Mariner on a rib that doesn't seem to worry about using last years petrol. Both use the same 50:1 mix, and are stored in similar dark conditions in the garage. The tender outboard gets a lot more use than the rib, so it's petrol doesn't lie around as long as rib engine petrol. I wouldn't attempt to use fuel that has been laying around for a longer period and has distinct smell that is totally different to new petrol.
Lakesailor
Well-Known Member
We had Nigel on these forums until a couple of years ago. He said that petrol doesn't go off. (unless exposed to daylight)
He was a fuel blender. I believe Nigel.
These people who have problems with "stale" fuel. Could it be that the oil is settling in the tank (and the float chamber) and the engine is being fed a very oil-rich mixture?
Could that be why draining the tank and flushing the carb solves the problem? I wonder if putting the drained fuel back in, after a shake up, would see the motors starting easily.
He was a fuel blender. I believe Nigel.
These people who have problems with "stale" fuel. Could it be that the oil is settling in the tank (and the float chamber) and the engine is being fed a very oil-rich mixture?
Could that be why draining the tank and flushing the carb solves the problem? I wonder if putting the drained fuel back in, after a shake up, would see the motors starting easily.
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VicS
Well-Known Member
I think you will find that Nigel Luther said a little more than just that.
He recommended, much as I do, that it should be stored in tightly capped cans to prevent loss of lighter fractions and minimise contact with air as well as minimising exposure to light.
(He last posted on these forums nearly five years ago)
The oil is completely dissolves in the petrol . I dont think you will find that it will separate any more than the solute will separate from the solvent in any other solution.
!
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Fantasie 19
Well-Known Member
We keep going round and round this one.. I will only repeat what the outboard engineer (with 60+ years experience) I use tells me - "never use last years fuel". He blames the newer additives..
I can't see any reason not to chuck it.. the stuff only costs a quid and a bit a litre, and I'd rather be able to rely on the outboard starting, than save a couple of quid....
In response to the OP, as per one of the other replies I usually slip it into the oil tank at the tip when they aren't paying attention, or just put it in a bag and put it in one of the skips...
ghostlymoron
Well-Known Member
It seems that some engines are more sensitive to old fuel than others. If you have a petrol car, adding old fuel to make up to a full tank seems to cause no problems. Otherwise, stick it in other engines a bit at a time.
daviddb
Well-Known Member
As long as it's not actually jellified I just stick it in any old four stroke engine of 'a certain age'. Neither our Ami8 nor either of the Quatrelles have ever complained. Out of an abundance of caution I'd be a little more hesitant about sticking it in a modern petrol engined car but then I Know nurthing...
VicS
Well-Known Member
Always learning something new. I thought that "gas" was short for "gasoline"
pvb
Well-Known Member
Lakesailor
Well-Known Member
Do you have any other insight into why I haven't had any problems with stale fuel
Alfie168
Well-Known Member
Spot on. No engine is going to notice that level of dilution. I've never known petrol go off either. My mower started about 4th pull the other day on the remains of last summers fuel in its tank.
Disposing of petrol at a council oil disposal point is an absolute no no. That creates a massive risk to other people disposing oil and also to workers there. Very naughty and dangerous.
Tim
VicS
Well-Known Member
No .
some people seem to have more problems than others. Some engines seems to be more susceptible to difficulties.
I always store the outboard 50:1 2 stroke mix from one year to the next but I do so as already outlined and I only keep full metal cans to minimise the contact with air and exposure to light.
Ever since I had to strip and clean a carb on a windy night in a busy river estuary I filter it before use. I also mix it about half and half with fresh.
Anything in excess of the two full (metal) cans I put in the car or use for the Seagull or the Flymo. Its these small "left overs" that have not been stored like the rest that cause any problems I encounter.
I doesn't matter much if the Seagull is unhappy because I can row the dinghy and it does not matter at all if the Flymo wont start because I can use the electric one or let the grass grow but if the main outboard plays up entering a busy river estuary with loadsa other yachts, mobos, car ferry, hydrofoil, chain ferry and a strong tide its rather more serious and I take whatever precautions I can that might avoid any such difficulties arising again.
Dougal
Well-Known Member
As a motorcycle technician, I can PROMISE the 'non believers' that modern petrol most definitely 'goes off';-) How quickly this happens involves many factors. I will also confirm that adding small amounts added to a tank of good fuel will NOT damage an engine in any way. If too much is added, the only issue would be 'POSSIBLE' damage to the cat. However, even this if done in small amounts, is not a problem.
The only time i wouldn't recommend this, is with high performance, tuned engines.
The only time i wouldn't recommend this, is with high performance, tuned engines.
lw395
Well-Known Member
Northern climate?
I've had stale fuel which seems to have stopped engines working.
But only very old fuel, which has been stored in vented tanks for more than a year.
I'm talking about 'project' bikes which have not run for 5 years.
It smells very wrong. Can't describe it.
One of my italian bike manuals says old fuel 'may turn sour' which does not describe the smell, its more of a sweet chemical fruit thing...
Fuel left in a small carb will tend to evaporate, which can cool the carb inducing condensation. This puts water droplets in the carb, which is IMHO the most common reason for small engines not to start.
As for getting rid of old fuel, unless it smells really odd, chuck it in any engine without a cat and dilute it with new fuel.
Do check or filter for water, dead spiders, rust.....
If it smells really odd, put it with the old sump oil.
prv
Well-Known Member
Well, one reason is that it can be quite hard to chuck. Our council has built a new dump and closed the old one, and there is now no waste oil tank. The place is also swarming with staff who scrutinise what you're putting in the skips, and anyway putting petrol in stuff I know is going to be incinerated does seem a bit naughty. I wouldn't have a problem with putting it in a petrol car in small quantities, but I now drive a diesel.
Pete
nigelmercier
RIP
- Joined
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- Live in Kent, boat in Canary Islands
I often hire a car when I go to my boat, an ideal repository for old 2-stroke.
I have many garden tools that will not start until I replace the petrol, possibly due to the fuel tanks being translucent.
I have many garden tools that will not start until I replace the petrol, possibly due to the fuel tanks being translucent.
RichardS
N/A
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
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
jac
Well-Known Member
My take is that plenty of people seem to have problems with stale fuel whilst some others seem to have no issue.
Have to say though I'm very surprised that so many people have so much fuel left over at the end of the season. Personally I'm not keen on carrying large amounts of petrol so buy a 5l can which I then use to top up the OB which takes 1.4l. It shouldn't be that hard to run down spare petrol supplies at the end of the season so that there is only a small amount left to dispose of either into the car or to be diluted with fresh petrol.
Have to say though I'm very surprised that so many people have so much fuel left over at the end of the season. Personally I'm not keen on carrying large amounts of petrol so buy a 5l can which I then use to top up the OB which takes 1.4l. It shouldn't be that hard to run down spare petrol supplies at the end of the season so that there is only a small amount left to dispose of either into the car or to be diluted with fresh petrol.
VicMallows
Well-Known Member
IIRC, Nigel stopped posting here because he was fed up with being endlessly challenged by tom-dick-and-harry on a subject on which he is clearly an expert. Our loss.