I was just thinking, the amount of time my car sits unused, what is happening to the fuel in the tank, lines and my cabs? I run BP Ultimate 98RON. When I go for a drive I usually just put about 10L in the tank.

From sitting for months at a time, could the fuel gum up float bowels, needle and seats, jets, fuel filter??

Should I be stripping the carbs down every now and then for a clean down?

Whats the time period for modern higher octane fuels to go off?

I know I need to replace all my brake fluid, its been in the car for 7yrs...

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http://www.youtube.com/user/Hanras

If the car only has a small amount in the tank when it's stored you'd want to have a good filter to make sure no dirt or rust or anything else in the tank settles and goes to the engine, that said, if you were to top it up with fresh fuel before driving the older fuel should be diluted enough so as not to be a problem.

fuel is only within spec for around three to six months if stored in an unsealed environment such as a fuel tank. You are better storing your car with either a full or empty tank as a half full tank is subject to a greater exposure to air. If you are going to store your car long term then you should drain the tank as fuel does become acidic and water laden when exposed - this will eat your tank. I would only strip carbs if you have a problem.

Brake fluid is only good for twelve months, with silicon fluid being slightly better as it obsorbs less moisture.

Ive got a filter directly under the tank (which has been on the car for 7yrs also) prob should replace it....!!! Its only done 10,000 miles!!!

Im more thinking about the fuel that is sitting in the carbs?

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http://www.youtube.com/user/Hanras

I wouldn't worry about fuel in the float bowls, if it's been sitting for a loooong time then it may well have all evaporated anyway. Even if not, it'll cough and splutter for a minute or so until you get fresh fuel in, then it'll be fine.

I'd be more worried about the inside of the tank than anything else... the rubbers may deteriorate and leak but nothings going to gum up (unless you use E10, then that's another story).

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Simon

The adventures of an owner builder in the Tallarook Ranges

Im led to believe though that since the braking system has standard fluid in it, for me to change over to Silicone now would be a big exercise in replacing seals and rubbers..?

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http://www.youtube.com/user/Hanras

Correct. Not worth the trouble and the cost IMO, unless of course you are planning to overhaul the entire system.

Most mower shops sell fuel preserver to prevent gumming and other problems associated with medium term fuel storage in fuel tanks and systems.

owen1975richard, I was fairly sure that BP (for one) only say their fuel will hold spec for 4 weeks, after which time the octane rating would be below spec (so when it is fresh, it is higher). When the fuel is manufactured, it comes out as (about) 91 unleaded and then they add all the herbs and spices to bring it up to what ever they recon it should be. It is the added herbs and spices that evaporate off, especially in pre-pollution type vehicles, that reduce the octane rating. So the octane (in theory) shouldn't go below 91. You'd probably be best off storing with full fuel tanks.

DO NOT use E10 if it is going to be 'stored' as it will seperate.

And as owen1975richard aluded to, it will be necessary to replace all the rubber components of the hydraulic system to get the best benifit from silicon brake fluid, but it would seem that there are silicons and silicons, some are good some are crap. Many also have a lower DOT rating than conventional brake fluid.

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I use 98. There are no fuel leaks in my car.
If I half fill it then park it for 3 weeks the fuel level drops by about 1/4-1/3 of that due to evaporation.
Who called this unleaded stuff petrol... it seems to have more paint thinners and other aromatics than petroleum.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thats a huge loss Doc, it should be more in the range of 3%.

Maybe so, in a sealed tank (ie an EFI car). Not with breathers fitted IMO.

Leave the lid off a tin of thinners and see how quick it goes down.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Interesting side note - for years ( and mainly when I was younger and 'tinkered' a lot with the car) every now and then I would chuck in about a cup of metho into the tank - theory being it would absorb any water and mix it with the petrol and burn it off in the engine. Ethanol will do the same thing so could that be the upside of the E10 debate?

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

Thats generally our acceptable loss rate in our tanks (above & below ground)

that's interesting...

I usually have my cooper in pieces over the school christmas holidays (5 weeks), and it will always run like crap until I get a fresh load fo fuel in it

Hanra, if you're worried about crap in the carbs, switch off the fuel pump and let the engine run out of fuel when you're going to store it - but it will evaporate out anyway

I work for BP, and I have a mate who works in the fuels technical area. I tried to pin him down on this very subject. I didn't start my Corona Coupe for four or five months and it barely limped the 1km to the servo when I did eventually get it out of storage.

Ultimate has a shelf life of six weeks. After that it goes off spec. His suggested solution was to try and put the car away with less than 1/4 tank every time it's not going to be used. Then top up every time I use it.

I asked him about fuel conditioners. With his BP hat on, he couldn't recommend anything. With his BP hat off, he suggested they might be worth a try.

He also admitted the old leaded Super stayed on spec a lot longer, even a couple of years. But that's impossible to obtain now.

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Brett Nicholson
Greendale (near Ballan) VIC.
1971 Morris Mini Moke
1966 Austin Mini
1965 Morris Mini Traveller
1973 LR Series 3 88
2007 LR Freelander 2