Blackened and sooty spark plugs

[hoppy]

May be a stupid question however over the winter period I have been turning my jeep engine over for about 10-15 minutes twice/three times a month; I just push it out of the garage and let it run.

 

 

Today I was able to take it out for run and it was coughing and backfiring like a good un. Came back and had a look at various things and found the plugs were heavily blackened.

 

 

 

 

After cleaning the plugs and cleaning bits up a second road run was perfect, SO is it a simple fact that the jeep was just run statically or is there some underlying issue?

[paulbrook]

Just out of interest was it OK before it was laid up? Also is it fresh petrol or the stuff that as been in the tank all the time?

[ruxy]

The original Gunson Colourtune plug was more or less shaped like a spark plug , the later version is more squat - this was done to enlargen the lens size to make it it easier to look through and see the combustion colour. The disadvantage is that what you need is to see the the combustion colour when the engine is under load. Rev up on the drive is only indicative , However - with a Jeep , what you do is remove the bonnet , get wife / girlfriend to drive - whilst you look into the engine bay and observe - stop & twiddle carb volume screw accordingly , re-check & sorted. Actually dawn, dusk or in the dark is quite interesting esp. if you have 4 qty Colourtune plugs LoL

[hoppy]

Just out of interest was it OK before it was laid up? Also is it fresh petrol or the stuff that as been in the tank all the time?

 

Runnning fine before laid up and the fuel is the same.

[paulbrook]

Modern fuel goes bad after about 30 days. It goes very bad after 90, having lost the "lighter" elements. This could well account for poor fuel air mixing and incomplete combustion. Incomplete combustion results in soot.

[hoppy]

Modern fuel goes bad after about 30 days. It goes very bad after 90, having lost the "lighter" elements. This could well account for poor fuel air mixing and incomplete combustion. Incomplete combustion results in soot.

 

This is one thought we had, one of my mate repairs lawn mowers, most of his work comes from mowers with fuel issues. Need to get out for a good run I think and see what happens; after I ve sorted a MOT.

[Pete Ashby]

Runnning fine before laid up and the fuel is the same.

 

In that case I would not concern yourself with any issues to do with the carb other than checking that your choke is coming fully off.

 

Pete

[Tony B]

A good dose of propritary spray carb cleaner wouldn't hurt. Funnily enough I was taliking about something similar yesterday. The mecanic of a company called Romeril's in Jersey had a trick. His Fleet consisted of four petrol engined Morris FG, for those of a certain age, the thrupeeny bit Saftey cab, every week he would run the engine up take off the air filter and spray water from a platic mister spary into the carb till the engine stuttered. He always claimed it cleaned the engine out and he didn't have to de coke them. I eventually ended up driving one of his ex charges about, on L plates!

[andym]

Forgive me if I'm being rude and teaching people to suck eggs, but you aren't blipping the throttle before you switch off, are you?

 

Andy

[Lauren Child]

If modern fuel sits for too long it turns into a rather nasty slime that starts to block filters and pipes. Here's some I prepared earlier. Carb cleaner is good stuff, but it's worth adding one of the additives to the fuel to stop it happanning in the first place.

 

Edited March 2, 2013 by Lauren Child

[paulbrook]

If modern fuel sits for too long it turns into a rather nasty slime that starts to block filters and pipes. Here's some I prepared earlier. Carb cleaner is good stuff, but it's worth adding one of the additives to the fuel to stop it happanning in the first place.

 

[ATTACH=CONFIG]73415[/ATTACH]

 

 

Yep that looks familiar - I did a 1950s Ford F1 Truck with a flathead V8 that had terrible fuel issues - much like Laurens sample there. It had a fungal growth too which these days isnt just confined to diesel fuel.

[hoppy]

Forgive me if I'm being rude and teaching people to suck eggs, but you aren't blipping the throttle before you switch off, are you?

 

Andy

 

Not intentionally no.

[hoppy]

Yep that looks familiar - I did a 1950s Ford F1 Truck with a flathead V8 that had terrible fuel issues - much like Laurens sample there. It had a fungal growth too which these days isnt just confined to diesel fuel.

 

Additive bought!

[paulbrook]

So heres the thing.

 

The lovely little Standart Tilly that has been in the Big Shed for a while went home today. Ever since the reconditioned engine went in it has behaved impeccably. Yet today when the owner arrived to drive it home it was having none of it, misfiring, popping back through the carb and all that. Plugs came out, black as the ace of spades so they got cleaned up. One plug continued to refuse to soldier so eventually I swapped that out for one out of a series 1 landrover which improved thing marginally but not completely. But fundamentally there was nothing wrong with it as it was all as per the book.

 

Eventually the owner got it out onto the road and between us we got underway, slowly at first but then with growing confidence and ever improving performance.

 

Within 30 minutes it was running like a sewing machine and in due course earlier this evening it was home after a fine 90 mile run. OK there may be some slight adjustments to be made to timing and idling but the fact of the matter was that these are not modern engines and need coaxing along sometimes, especially when coming out of hibernation.

 

They are not formula 1 cars requiring constant adjustment (think of the standards of the day when they were built and what they were for after all), but they do need to be used - and for decent amounts of time. Theres nothing like a good long run to blow the cobwebs out and get everything settled down. Only then should you contemplate getting the toolbox out!

[Pete Ashby]

So heres the thing.

 

The lovely little Standart Tilly that has been in the Big Shed for a while went home today. Ever since the reconditioned engine went in it has behaved impeccably. Yet today when the owner arrived to drive it home it was having none of it, misfiring, popping back through the carb and all that. Plugs came out, black as the ace of spades so they got cleaned up. One plug continued to refuse to soldier so eventually I swapped that out for one out of a series 1 landrover which improved thing marginally but not completely. But fundamentally there was nothing wrong with it as it was all as per the book.

 

Eventually the owner got it out onto the road and between us we got underway, slowly at first but then with growing confidence and ever improving performance.

 

Within 30 minutes it was running like a sewing machine and in due course earlier this evening it was home after a fine 90 mile run. OK there may be some slight adjustments to be made to timing and idling but the fact of the matter was that these are not modern engines and need coaxing along sometimes, especially when coming out of hibernation.

 

They are not formula 1 cars requiring constant adjustment (think of the standards of the day when they were built and what they were for after all), but they do need to be used - and for decent amounts of time. Theres nothing like a good long run to blow the cobwebs out and get everything settled down. Only then should you contemplate getting the toolbox out!

 

Wise words indeed enough said.

 

Pete

[Tony B]

I'd say the other way around. My old Dodges will run in conditions that modern vehicles would disintgrate! :-D

[hoppy]

Just an update, ran the jeep up and took it for MOT (there was another thread on brake light switch due to brake issue) and had a good 12 mile run. Ran fine after couple of minutes. Also had the garage look at the carb (classic vehicle only garage) superb mechanic who said no issue with carb at all. Fingers crossed...................................