Fuel going off!

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TonyG
Posts: 288
Joined: Mon Sep 07, 2015 4:38 pm

Fuel going off!

Post by TonyG » Mon Apr 06, 2020 9:38 am

Hi all,

I know that Petrol degrades over time and that modern lead free ethanol based fuel is particularly bad. However, I’m having real trouble with my Tourer and wondered if others were finding that this issue is getting worse?

A couple of months ago I drained all the fuel from my car and replaced it with newly purchased Esso super unleaded. This was to resolve non starting issues that I’d traced to deposits in the carbs. With everything cleaned out and fresh fuel all was ok. However, when I wanted to drive the car a few weeks ago it was, once again, a struggle to start and mis fired badly. Also required a lot of choke to run at all. Investigation showed that the Petrol had gone off again. Suitably replaced it now starts on the button, as it should.

It seems that Petrol in the tank and in the float chambers is going off in a matter of weeks. Knowing that the tank is open vented and wanting overcome this while the car is standing unused I’ve plumbed in a temporary fuel pipe in the boot that can take Petrol from a gallon can and be re sealed when not in use. Obviously not suitable for road use but saves me draining the tank every few weeks. Going to be a real pain once the lockdown is lifted and I start using the car again, unless I drive it daily and add new fuel regularly. Not a bad idea in many ways.

Researching this subject on the Internet reveals that modern Petrol has, indeed, got a shelf life of just a few weeks. This is particularly apparent with carburettor engines since fuel injection vaporises the petrol, making it more combustible. The ECU on modern cars also allows for different octane levels etc. The old petrol works in my lawn mower but does foul the plug quickly and I’ve read it can be put into modern cars in small amounts to use it up. The Esso super should be ethanol free, according to the Esso web site but I’m not convinced that the tank at my local co op is replenished often so it may have already degraded before I bought it. Petrol is almost clear like white spirit when new but yellows with age as various elements vaporise away. The first to go is the butane which is added to aid easy starting but there are over 100 other elements added into the petrol.

My experience is that this problem with petrol has got worse over the past year or so resulting in poor starting and short plug life. I may be more aware of this because my car has higher compression, which will make it run worse on poor fuel but I’d be really interested to know if anyone else has had similar problems and how you have got around them? Also I suspect that the lead replacement additive was separating and creating a red brown residue in the carbs but this is also a symptom of degrading fuel I believe.

I look forward to reading your replies whether you have had similar problems or experienced none at all.

Many thanks

Tony.
Tony Gilbert

P1 12 Tourer
P2 12 6 Light Saloon
Discovery 3
Discovery Sport

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luli
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Re: Fuel going off!

Post by luli » Wed Apr 08, 2020 2:20 pm

Hi Tony,
I never had it so badly but I have noticed that older fuel may require stronger sparks, and clean fresh spark plugs.
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TonyG
Posts: 288
Joined: Mon Sep 07, 2015 4:38 pm

Re: Fuel going off!

Post by TonyG » Fri Apr 10, 2020 3:21 pm

Luli,

Thanks for your reply. I have another coil, which I will try. I’m getting through a lot of plugs as well so it could be that this is also the reason for that. The old petrol does leave a lot of carbon, which could be a factor. Similarly, a poor spark.

Regarding the plugs, I found a set of Champion J8s that were in the car when it was dismantled in 1982. The plugs were probably a number of years old then! Having had a number of NGK B6HS and B5HS fail I put in this old set and never had a problem. However, these are now obsolete and, not wanting to rely on such old plugs, I got some J8Cs from the Green Spark Plug company along with some NGK B6Ss. I’ve had both fail on me. I had hoped that the shorter reach was the reason the old plugs were more successful but I may have been misleading myself. Reading the NGK site they say the most common cause of plug failure is incorrect torquing when putting them in. I don’t think I’ve read anywhere what the correct torque is for my car but it is something I will be mindful of.

Tony.
Tony Gilbert

P1 12 Tourer
P2 12 6 Light Saloon
Discovery 3
Discovery Sport

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