petrol additive /'preservative'

[Mikey D]

quick query for the collective

my motorbike gets rarely used theses days , The fuel has usually 'gone off' ewhen i actually want to /have the time to use it .

i seem to remember some kind of additive , preservativre if you like ,being mentioned recently.

would i be better off using a high octane /premium petrol before laying up ?

cheers Mike

 

[cardiffrob]

I use STABIL in the aeroplane. Chainsaw additive. Seems to work.

 

[W4yne]

Fuel Preservative

Hi Mike,

Is this what you are looking for?

http://www.frost.co.uk/automotive-tanks-products/por15-fuel-preservative-stabilizer-us-pint.html

quick query for the collective

my motorbike gets rarely used theses days , The fuel has usually 'gone off' ewhen i actually want to /have the time to use it .

i seem to remember some kind of additive , preservativre if you like ,being mentioned recently.

would i be better off using a high octane /premium petrol before laying up ?

cheers Mike

 

[rich r]

Briggs and Stratton do one too (aimed at lawnmowers obviously). I suspect you'd get that from big DIY places.

There are quite a few 'petrol stabilisers' around. Most contain various chemicals designed to prevent the more volatile parts of the mixture of hydrocarbons that is petrol from evaporating or chemically changing.

The places to look are places that supply things for boats, chainsaws, lawnmowers, light aircraft, generators etc - basically petrol powered things that don't necessarily get used every day.

 

[Lawnmowerboy]

It is because of the "biofuel" content of the fuel. Supermarket fuels can be up to 10% ethanol which degrades all rubber in most fuel systems, Super unleaded is still just straight petrol and dosen't go off so quickly.

 

[Terrapin]

It is because of the "biofuel" content of the fuel. Supermarket fuels can be up to 10% ethanol which degrades all rubber in most fuel systems, Super unleaded is still just straight petrol and dosen't go off so quickly.

Correction here .............

HOW PETROL CHANGES IN EQUIPMENT TANKS
Loss of light components – impact on mixture
The light components in petrol are lost first as the petrol sits in the fuel tanks. These components provide valuable octane benefits during cold start. Because they are volatile they compose most of the air fuel mixture during cold start, if they are absent then the mixture becomes lean resulting in higher temperatures, pre ignition, detonation and piston damage. This is generally the cause of piston damage in high revving engines used in boats and small engines such as chain saws etc.
The portion of the petrol that remains has a higher density and higher octane but this is not available during cold start resulting in hard starting. Because the fuel carburetors and injectors operate on a volume metering system the higher density means that more fuel is introduced for a given volume of air and so the air fuel ratio is fuel rich. If all the fuel cannot be burnt then it forms carbon deposits that will foul the spark plug and cause the engine to stop and not start. This is generally the cause of problems in classic cars where the engine stumbles and hesitates or cuts out.
Loss of light components – impact on octane
The light components in petrol are lost first as the petrol sits in the fuel tanks. These components provide valuable octane benefits under high revving conditions such as cold start acceleration and the loss of these components can result in detonation and pre ignition at high speed resulting in piston damage.
The remaining components that have not evaporated are high octane and octane can actually increase with time but this octane is not available for high revving conditions.

............. from one who works on a major refinery

 

[madkayaker]

All unleaded in the uk can contain 10% bio fuel not just the supermarkets. Any more modern vehicles will tolerate this as its been standard for a while now is 20+ year old vehicles that may have problems

 

[Fazerruss]

Do these fuel stabilisers have any effect on the CAT. Reason I ask is I think all modern motorbikes now have them and the age of the bike was not mentioned in the original post.

 

[busastars]

I've had fuel problems in my bike recently from lack of use, drained the tank, ran the bike to drain the carbs, fresh gallon with a dollop of RedX and a good thrashing down the bypass cleared the carbs.

I've never noticed it in the past with fuel going off but these days it seems so common.

What would be the best thing to stop carbs gumming up? Shut of the fuel tap and let it run till it dies or drain the float bowels till you use it next?

 

[Robotstar5]

I drain the tank & carb bowls over winter, works for me

 

[hareng]

If you shut fuel tap off it will still have petrol in the float bowl.

Know what you mean had to nippers last year. Max time off the road was three weeks and gummed one of the jets up.

 

[hotrodder]

I thought the 10% ethanol thing is supposed to happen next year? It's environmental rules and at the moment in the UK i thought it was upto ~5% didn't need to be declared as containing ethanol at the pumps.

Super unleaded isn't necessarily free of ethanol. The FBHVC and/or some clubs (TR register is one i think) have stuff on their sites including lists of which flavours of super unleaded are supposed to be ethanol free- last time i looked it varied by region for BP ultimate (!?) and whatever the current flavour of Shell is called they won't comment . The story at the moment is that super will be exempt from the mandated increase in ethanol content as the jury* is still out on how much/how quickly the stuff 'eats' bits of of the fuel system in older cars

I forget what the exact score is but doesn't ethanol act as an octane booster in petrol? It's also hygroscopic which won't help matters with lightly used vehicles


* At least, I haven't found anything that's definately unbiased yet

 

[Mikey D]

Cheers Guys , helpfull as ever

fazerus , its a Bmw F650 GS , YEAR 2000 fuel injected ,no cat because i fitted a sebring exhaust .

What are you carbs of which you speak ?

The por 15 additive from frost looks the stuff but a bit pricey £20 ish with the post .

Will call into my local agricultural supplier and see if they have any stabil (cheers cardiff rob) or similar http://www.goldeagle.com/brands/stabil/products.aspxve

cheers Mike

 

[rocketron]

the posts replied to you are all very valid. there is another phenomenon called "phase separation"(google this and be horrified), and many additives/stabilisers will not prevent this. Modern fuels with ethanol are hygroscopic, i.e. they will suck up moisture, from anywhere. we see it so often at work (we are Mercury/mariner main dealers). In fuel tanks, moisture goes in via the tank breather.

If you store your engine with any fuel remaining anywhere, even if you think you have drained it completely from carbs, filters and tank etc, I would still use stabilisers which specifically says "prevents phase separation"

We have newish four stroke outboards where petrol (with ethanol) was left in the VST, a float chamber for fuel injection, where the high pressure fuel pump lives, and have "rubber" seals on inlet and outlet of this pump which have completely softened and thus mishapen. These are two year old models, rigged to withstand the affects of ethanol.

As an experiment, 3/4 fill a jam jar with fresh petrol and allow to stand for 5hrs, say, put lid on and shake for a minute. Allow to stand for 4-6hrs and the cloudiness will clear.Roughly this happens:

Three layers will be seen. NB, I'm an engineer not a chemist, but this is what we've seen many times.

Top layer, very poor quality petrol, will ****** up injectors and in many cases cause corrosion to carb float bowls, which re-occurs. will not run an engine.

Bottom layer, petrol smelling water, totally useless, will deffo cause corrosion, anywhere.

Middle layer, a thin "*****" like layer, (honestly!). this is ethanol, separated out from fuel because the "balance" of petrol constituents base been upset due to "phase separation". The water constituent in petrol has been increased thru being hygroscopic,

the ethanol layer has also caused the water part to be more slippery and and will pass through water separating filters.

It also breaks down the lubrication properties of two stroke mix, so rings, bores big and little end failures will occur.

Since oils float on water, this water is at the bottom of the tank and will be the first to be pumped to the carbs etc.

Such fuel will quickly set off this reaction in new fuel if added.

Filtering or shaking has had no effect on re forming the fuel to something useful.

Until about Jan this year, there were no treatments available to counter this. Mercury Marine now has two treatments available and we use these side by side, they're called Quickstore and Quickclean. We are satisfied this prevents problems.

Ok, this describes a worst case scenario, but trust me, this happens. Often.
Having been involved with vintage cars since 1969, which most are stored at least every winter, with fuel remaining in their tanks, am now seeing the odd problem with fuel supplied last October!!

For me, I would run treated fuel through for through last few miles, turn off supply and allow to stop. You can run fogging oil or storage seal into air intake and allow this to stall engine, if you want. then drain down everything.

Hope this is of some help.