Author Topic: Fuel Stabilizers  (Read 751 times)

David S

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Fuel Stabilizers
« on: October 11, 2015, 02:18:09 PM »
Does fuel deteriorate over time? Does it deteriorate in breathing tanks or sealed cans or both? Does it deteriorate in a can if full and sealed?

I guess you know where I'm coming from. I don't use all my petrol powered engines (bikes, cars, mowers, strimmers) all of the time. Some stand for weeks/months at a time.

Now, if the answer to any of the questions above is 'yes' then are fuel stabilizers a solution? If so, to what effect and for how long?

A search online offers every possible answer so its easy to go with one that suits your own gut feel but, what is the truth?

The easy answer is to use all petrol engines regularly or drain them when out of use but lets be practical.

Can anyone  point to an authoritative and independent report/review that will help answer my questions, svp.



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Re: Fuel Stabilizers
« Reply #1 on: October 11, 2015, 06:54:48 PM »
The question of fuel degradation has been one I've heard asked ever since I joined my first bike club, back in the 70's...  Whether or not fuel 'goes stale' or 'loses octane' used to be the most common queries...

Nowadays, whether or not modern fuels might actually damage elderly fuel systems is also a common query...

When I first started biking, fuel left in carbs when the bike wasn't used for long periods (usually during periods of recuperation) would evaporate away, leaving a 'red dust' precipitate behind.  When new fuel was allowed into the system, this 'dust' woud block idle jets, emulsion tube drillings and tiny aiways, resulting in horrendously poor running...

Nowadays, fuel evaporates away and leaves a kinds of 'mossy varnish' behind... This gums up fuel and air circuits, often completely jamming up fuel inlet valves and float pivots.  Poor running is also caused, but I've also seen hot engines awash in overflowing fuel - fire couldn't have been far away... :o

The old Mikuni carbs on my collection of XS1100s have always bee susceptible to fuel 'contamination', with even short periods out of service resulting in a need to dismantle and clean the carbs...

The XS sold tens of thousands of units in the US of A, with many owners living is States where their bikes would often lie fallow for months, so the need to avoid constant carb 'tear-downs' was crucial... I've seen plenty of chat about products that avoid contamination, stabilise fuel and even clean out fuel systems, but I've only used one myself:  Sea Foam

I bought three cans via Amazon UK (most economic option) and I've used one in my XS1100LG... The bike had been 'laid up' over winter and was exhibiting symptoms of blocked airways, etc... I used the Sea Foam, as directed... It appears to have sorted the problem completely ...

More info on modern fuels and how they can affect elderly fuel systems can be read on the Federation of British Historic Vehicle Clubs website; here:  FBHVC Fuel Info Page

Hope that helps

1975 Triumph Trident 750 (New Project)
1980 Yamaha XS1100 (Midnight Special)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Reg'd 1985)
1982 Hesketh V1000 (Pre-Production Engine)


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Re: Fuel Stabilizers
« Reply #2 on: October 13, 2015, 03:41:18 PM »
Sorry no chemist but just a few observations
A lot depends on the machine , if its an early one less well tuned, vintage then I would be happy to just give it a run after a winter lay up, if you know its the last run before its to cold to go out then drain the carb and if you have any old t/stroke oil dump that in the tank before it stops. Keep the tank as full as you can , you can always put it in the lawn mower, this stops the rust , water in the fuel and the corks drying out.
Though its an old diesel the best I have achieved is 80 plus years old heating oil in the tractor with success ;-)
The newer machinery depends on seals and o rings which do not like the new fuel so drain and squirt some oil in and on everything including the engine.
WD40 is better than nothing but it does contain water.
If you leave the carbs dry they corroded with a white powder which is a bugger to get out.
When you get on the bike next spring and its running a bit rough put a tank full of mileage through the carb before you start pi**ing about with it as if you can get away with it its the best way of washing the crud out.
Rambling of an old man about to rush south for some warmth , wine and sunshine and try and keep away from the cake shop  8)
I shall worry about all that old petrol if pushed really hard, maybe!