Classic cars forum & vehicle restoration.

[Bayliss Thomas]

On my new (to me) vintage car I understand that it hasn't been used for one year and its still has the old petrol in from that run out. When I had an test run out prior to purchase the engine did start, albeit after about 4/5 cranking episodes, and the engine ran only on 4/5 of its six cylinders. I thought perhaps an duff plug/lead or two. Thinking on and before car is delivered to me perhaps its the stale petrol causing the engine to run not firing up on all cylinders??
My first job is to drain out the old fuel and I would like to flush the system through. Advise sought on flushing products and the fact the car has rear fuel tank with Autovac pump system. Thank you.

[baconsdozen]

I wouldn't waste the fuel thats in it.Apart from cleaning and degreasing you can probably add a few pints every so often to a full tank.If there's hardly any in it and the car does at least start and sort of run you might get away with filling it with fresh. I'm always wary of flushing fuel tanks in case you stir up the junk thats in the bottom and block the filters etc.
Petrol gradually goes stale in a tank,after a year or so it will have lost some of its more volatile components.
You can buy devices that you put in the tank on ebay that its claimed will stop this happening. Total drivel.
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Thirty years selling imperial hand tools for old machinery(Now happily retired).

[Kelsham]

I suffered from stale petrol when trying to start an old BSA Scout, sidevalve engine.
I discovered it would start if given a new supply of fuel, fed through a spare rubber pipe up to the petrol pump.

Once warm it ran well until switched off and allowed to get cold.

Regards Kels

[Jim.Walker]

If you think you have stale petrol SNIFF IT. You will have no doubts and you will not be keen to sniff it again!
Unleaded fuel contains extra "lighter" fractions to offset the detonation tendencies that the "lead" controlled and therefore goes stale more quickly than the old stuff. Particularly in older cars where the fuel tank is vented to the atmosphere.
Flushing is probably not necessary and unless you have a tankful of "stale", adding a greater quantity of fresh will probably be enough at this time of the year.
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[michael1703]

ive just been given a car thats not been used for 7 years, it started fine on the fuel that was in it

but...

ive had vehicles sit for less than 6 months and the petrol was only good for the parts washer

buy a length of copper ht lead in and make up a new set of leads, it can make a world of difference

[Bayliss Thomas]

Thank you for advise and comment, I shall let you know how I get on in an couple of weeks or so.

[Nic Jarman]

The Morris would not start and it was stale petrol. I had a gallon or so in it so I put 2 gallons of fresh petrol in it, took off the fuel line and ran it through. Started no problem.
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1936 Morris 8 Series 1
1973 MGB roadster
1977 MG Midget 1500
Dax Rush

[Bayliss Thomas]

The engine was persuaded to start after 4/5 starter episodes but would only run on 4 or 5 cylinders not sure how many, but it was consistent. Would stale petrol cause this.

[Jim.Walker]

I suppose its possible if one or two cylinders are not up to par. More likely though it is through lack of compression with valve or piston trouble. If the misfire is on adjacent cylinders it could mean a head gasket problem.
I think a compression test is called for.
Of course if a compression test shows OK, you will need to suspect the ignition system.
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[Bayliss Thomas]

Thanks for input Jim, I will start with the ignition and work through as best I can, once I have fresh fuel in of course. I think the head gasket is OK as no signs of that having blown at all, thank goodness. As the car has been idle perhaps It may point to the valves.

[michael1703]

just a thought, how many carburettors does the car have?

six cylinder car but you dont say what it is

[Jim.Walker]

[Castellated nut]

My Rover 12 seems to run best on year-old petrol. I put it down to loss of the more volatile components and reduced octane. If it wasn't for the storage difficulty I would stock-up on petrol one year for use the next!

I did have problems last year though (sticking pump valves and carb. needle valve) when I put in some fuel about 4 years old I'd left in a 2 gallon can.

[Bayliss Thomas]

I'm in the process of buying an Vauxhall 20/60 saloon of 1927 vintage, its been in fairly long term ownership and not used very much apparently. The cylinder head has been completely rebuilt at some point in current ownership. The engine sounds sweet other than pre described problem.
The engine is running on an single Zenith carb'.

[Salopian]

Is this the SV reg one that was about for sale recently? Ex NZ I think. Always wondered about the GM Vauxhalls as they seem well made and useful cars which suffered from not being a 30/98 if you see what I mean. I suspect for your towing (if I read the news right) this is a good choice. Seem to recall the engine was enlarged later in production but could be wrong.
If its stood try new spark plugs - I find NGK in particular seem to foul when stood and will not revive even after cleaning. Had a similar annoying misfire on the Sunbeam (also a 3 litre six) and it was this.
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Jonathan Butler
Alvis SD 12/50 1928 MG TD 1950