Stale petrol

[Pdv]

Hi

What do you guys use to stop petrol going stale if you use your car infrequently.

I knew that it went stale, however over the years have never had petrol that smelt off though, but was told recently that it could be as little a couple of months.

Thoughts on this subject would be appreciated.

Steve

[Clive]

Use the car more! But in all honesty, I have a spit that has had the same fuel in for about 8 months, no problems. Think it may be a myth??

I am sure there are some additives available if you are concerned. No idea what they contain though. (snakeoil?)

[Colin Lindsay]

My GT6 went off road in August 2018 and restarted in February 2019 using the same petrol that I had drained and was intending to use for the lawnmower; when it came to restarting I had nothing else at hand. It seems to run perfectly well and if there's any drop in performance I can't tell at present.

[SixasStandard]

When I bought my Vitesse in January I got the seller to fill the tank, as I was anticipating driving the car back from Devon to Lincolnshire. That didn't happen (it's a long story) and I ended up having to have the car trailered back, so I still have about half a tank left now. I went out for a run in the car yesterday to test all was well after a recent steering gaiter change, and the car performed faultlessly.........so I'm with Clive on this one. The idea of fuel going stale might be true for stuff that's years old.......but my experience is that it's still fine after 6 months.

Ian

[Pete Lewis]

I have never come across any stale fuel issues ,  Im with Clive  its a Myth generally confused with other running problems but the fuel gets the blame game

and i would also avoid must have additives you dont need 

most fuel problems stem from owners using a can to top up and its contaminated with what ever preceeded the petrol

Pete

[dougbgt6]

I'm a wimpy fair weather driver and leave the car in the garage sometimes from October till April. Never had a stale fuel problem. In fact before I decided to get the beast running again it sat in the garage for 15 years and I would start it up now and again, it was about the 12 year mark it wouldn't start, but that eventually proved to be a leaking manifold gasket.

Having said that my petrol was the "good stuff" 5 star, petrol now is very different. Ethanol! Horrible stuff 5% in a lot of fuel and soon to increase to 10%.  However most garages sell "better" unadulterated fuel, stick to that.

If your still worried best plan is a strategy, don't fill up to the max, keep the tank low and only top up with what you need. So after a bit off a lay of down to the petrol station to top up with fresh.

Doug

[Chris A]

I park mine up for winter with just the occasional start and if possible run to keep things ok. I just leave it as is, if the tank is full so be it, if nearly empty so be it. Never a problem restarting due to stale petrol. The last "won't start" problem this spring was after a run and a bit of a clean inside the next time I tried to start it dead! Battery finally given up the ghost? Put on charge tried again, no problem. Culprit? The driver! He had accidentally knocked the dashboard light switch to "on" so the battery has slowly run down.

I would say that battery condition is more likely to cause problems after a lay up, ignoring driver error of course.

Oh, I agree DRIVE IT MORE !!

Oops! Now I've opened another old debate topic . . . 😱

[Badwolf]

When I mothballed mine in 1996 (I think) it had some 4 star leaded left in the tank. Ran well while trying to free off the clutch in 2018, but soon got topped up with new higher octane stuff. Tank is currently full of last year's higher octane.... we will see.

[NonMember]

I've had what certainly seemed to be stale fuel problems when my GT6 was accidentally laid up for three years. The difficulty getting it started again was probably mostly down to gummed up carbs, though (I'd replaced the dead battery and the corroded starter cables). It needed easy-start. Once running, it was decidedly not happy until it had got properly warm but after that it seemed OK - drove to its MOT a couple of days later with no obvious issues.

[JohnD]

I build my engines to the highest CR I think will not knock.      With modern 99 octane fuel that means a bit less than 11:1.

One time, I didn't take care to drain the fuel overwinter and started on what there was in the tank - and it knocked like mad!     Fill up with the good stuff and no more probs.

Modern, lead-free, alcohol-containing fuel is a complex mixture of different compounds, all of which have different vapour pressures and which can be lost from an open storage container at different rates, losing octane rating and other properties.     Fuel in a sealed container will be stable, but not in your tank.

Today, I drain the tank before winter, as I can use the lifter pump that keeps my swirl pot full to pump the main tank dry.    I can just plug a dry-break connector into the pot.  More difficult to do unless you have an electric fuel pump and are willing to get your hands a bit wet with fuel!      But I also add some Fuel stabiliser, as I can't empty the pot!.     Stabilisers are usually sold to be added to lawn mowers over winter!     This has prevented restart knocking for me.

John

[Neil Clark]

A few years ago I bought a wonderful Mini Clubman that had been laid up in 1985, and forgotten about in an elderly lady's garage until 2016 covered in gunk and junk.  In that case the fuel had evaporated and left a solid tarry deposit that gummed up the fuel tank, fuel lines, carbs etc, that I did not spot in my excitement at getting it (it only had 8500 miles per the MOT's and was rust free).  When I immediately and stupidly added new fuel it semi-dissolved the gunk and it took a lot of work to clean it out.   But John is right I think that if fuel hasn't actually solidified, all you lose is some volatility.

(I sold it a year or so afterwards - I just hated what was happening to it every time I added a few miles and the thought of it deteriorating.  Here it how it looked after a simple machine polish. )

[Dick Twitchen]

27 minutes ago, JohnD said:

Stabilisers are usually sold to be added to lawn mowers over winter!

Very widely used in the marine world with outboard motors that may/may not be used for some time.  I put it in the remote tank for mine at the start of the season (Easter) and fuel is fine throughout the year until October, and that is leaving the vent cracked open slightly to avoid the tank over pressure in the heat.

[Colin Lindsay]

12 minutes ago, Neil Clark said:

A few years ago I bought a wonderful Mini Clubman that had been laid up in 1985

My sister-in-law had the exact same car, same colour and all, and to my shame in 1986 I wired a radio into it for her; so well that every time she turned it on, the car stopped. That photo brings back memories that I'd rather forget...

[poppyman]

Stale fuel will smell of turps or white spirit, but engines for road use will still run once you have got it started. It's just not as volatile so you will have to start an engine on brake cleaner a splutter a few coughs and off you go to the petrol station for new fuel a bit of smoke maybe, but it will run. I wouldn't try on a car with a "cat" or newer moderns, but pre "cat" should be ok.

Tony.

[Graham C]

Neil, I had a mini clubman estate in the same colour, it was my Mum's and passed onto me. The BL Chustnut Brown was a wonderful colour when polished.

I sold it to buy my Spitfire which I still have.

Really enjoyed the mini. Amazing how many different styles of cars came from the mini. No one really does that anymore.

Graham

[Neil Clark]

I started with a 1963 Austin Mini Woody. They are part of our DNA these Mini's.  

[dougbgt6]

I had a surf blue Morris mini woodie, 10 years I had that car, everything that could go wrong with it, did. I loved that car, then I bought a Triumph.and, much the same! 😆

Doug

[Unkel Kunkel]

I don’t know how long petrol remains useable but I have had a curious  gelatinous fairly clear,  goo clog up a small generator carb. that I forgot to drain and it was  a tedious job to sort.

It isn't easy to fully  drain  some vehicles or machines, and they can stand idle longer than intended

I started using this stuff - maybe unnecessarily, who knows?
-  but  I haven’t had any problems since and it costs very little ( under £2 a bottle)

“Dose“ is 50ml  per  15 litres petrol (With very little petrol in a tank pro rata only a tiny amount is needed) 

[dave.vitesse]

I have just been checking the TR7 ready for it's MOT. Part of the check was the CO level which must be between 2.5 and 4.5 CO. I normally set this to 3.0 to 3.5 CO, but it had risen to over 6.0 CO. After ensuring there were no other problems the major cause was old fuel.

Dave

[68vitesse]

The lawn mower is the only petrol engine item I have that doesn't get used all through the year, stick it in one of the sheds after last mow with what ever petrol is in it. Following year when I can't leave the lawn any longer never been a problem starting it.

Regards

Paul

[Chris A]

1 hour ago, 68vitesse said:

 Following year when I can't leave the lawn any longer never been a problem starting it.

Regards

Paul

Same here. Although I move mine from the shed to the boiler room/workshop for a few days before its annual "service" and first use.

[Unkel Kunkel]

I think my  views on petrol have been rather skewed  by a week-end battle  in 2018 , cleaning out an ancient copper petrol tank which needed agitation with lengths  of chain, steam from a converted wall paper stripper, acetone and  several   hours of citric acid at 50 C.

”That’s the replacement tank, as well” remarked my  oppo. as we  finally refitted the it.

“Oh, so when was it replaced? “ 

We checked...

 - 1946

 

 

[68vitesse]

1 hour ago, Vanadium23 said:

 

”That’s the replacement tank, as well” remarked my  oppo. as we  finally refitted the it.

“Oh, so when was it replaced? “ 

We checked...

 - 1946

 

 

Nothing made to last these days.

Regards

Paul

[Gary Flinn]

I have had a few issues recently with starting and Rough running with my current Classic car which I suspect was down to oldish Fuel although I don't know for sure?

After cleaning out a Needle Valve on the carb and adding some new Fuel the car started 2nd turn of the key and ran as smooth as ever?!!

I've had recent E-Mail correspondence with Martin the guy who is the latest custodian of my old Vitesse and he told me the car recently refused to start after a 6 month lay-up.

He drained the Fuel and replaced with new and the car started up 1st time?

He also stated he's subsequently used the old drained fuel in his Petrol Lawn Mower and it was fine when used in that.

There is no doubt this new modern Fuel can cause trouble with old cars, in particular the Carbs & Petrol pumps.

I hope all you fellow classic car owners have changed your hoses to the Latest R9 or R14 Specification too.🤔       

 

[poppyman]

2 hours ago, Vanadium23 said:

I think my  views on petrol have been rather skewed  by a week-end battle  cleaning out an ancient copper petrol tank which needed agitation with lengths  of chain, steam from a converted wall paper stripper, acetone and  several   hours of citric acid at 50 C.

”That’s the replacement tank, as well” remarked my  oppo. as we  finally refitted the it.

“Oh, so when was it replaced? “ 

We checked...

 - 1946

 

 

And i bet it was only just out of warranty.....

Tony.