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?

[welshbayonetww2]

hi, I suggest its because when you run the engine for a few minutes it wasn't hot enough for complete combustion and hence the soot. Should be fine after a long run and cleaning the plugs. If it doesn't sort itself out, the piston rings may be passing oil... look for a lot of blue smoke out the exhaust.

 

hope this helps. Doug

[Degsy]

It could also be running too rich.

[Jack Innes]

Your plug looks to be "sooted up" from running rich for short intervals. The choke is intended to make the mixture ritch thus the soot.

 

You are doing your engine a severe disservice by running it for short intervals in the winter. Look at the exhaust pipe of a cold engine running & you will often see water running out the pipe. If you must start the engine it is wise to run it up to full temperature to evaporate as much of the water created by condensation on the cold internal parts. Otherwise the water just stays in the combustion chambers & can cause great corrosive damage. ( It is illegal to start a piston engined aircraft in storage without running it up to full operating temperature. Failure to do so can result in a major engine overhaul demanded by the MOT. )

 

Much more advantage in preserving an engine in storage can be accomplished by disconnecting the coil wire & turning the engine with the starter once in a while. This will distribute oil where it is needed but will not cause the condensation previously described.

 

In the spring remember to re-connect the coil wire --- I will not publicly admit to why I suggest that!

[David B.]

Off at a slight tangent - I have a couple of sets of difficult to replace 3 point screened plugs in a very sooty state through similar use which I would like to clean up properly - rather more than a rub up with a wire brush.

 

Does any one know of or have one of those old Champion ( I think) blast cabinets which were used for the thorough cleaning of spark plugs in garages some years ago ?

 

Thanks - David.

Edited February 23, 2013 by David B.

[fv1609]

David there are lots of these around:

 

http://www.ebay.co.uk/itm/Gunson-77111-Tuning-Spark-Plug-Cleaner-Tool-Garage-Auto-/330832876563?pt=UK_Hand_Tools_Equipment&hash=item4d072d1413

 

Gunsons seem to have started to produce them. For ages the only ones advertised were in the USA with high carriage costs. For some years I have been using a "Wally" from Italy it leaks grit a bit round the top were the plug goes in, hence these new ones have a shroud.

 

Only blast for the minimum length of time to minimise the damage to the insulator.

 

I always used to regard a blasted plug as being as good as new, but this is not the case it will require more HT to get a spark unless the contacts are filed & reset. Although that may be difficult with a multi contact plug.

[wally dugan]

HI

 

I would like it to be known that CLIVE has not used me to clean his spark plugs and I do not leak GRIT

 

 

REGARDS WALLY

[fv1609]

HI

 

I would like it to be known that CLIVE has not used me to clean his spark plugs and I do not leak GRIT

 

 

REGARDS WALLY

 

Oh so you're not from Italy after all, so how do you do it Wally? A wire brush sounds a bit uncomfortable

 

 

PS I see my Wally is from Milano, so I think that's Spain not Italy :red:

[Nick Johns]

Oh so you're not from Italy after all, so how do you do it Wally? A wire brush sounds a bit uncomfortable

 

 

PS I see my Wally is from Milano, so I think that's Spain not Italy :red:

Clive, you should have used that pic as the next "mystery object" !

[fv1609]

 

Clive, you should have used that pic as the next "mystery object" !

Shot myself in the foot again!

[fv1609]

As regards what others have said about taking the vehicle for a run, this is the official view as well.

 

[Degsy]

Oh so you're not from Italy after all, so how do you do it Wally? A wire brush sounds a bit uncomfortable

 

 

PS I see my Wally is from Milano, so I think that's Spain not Italy :red:

 

Milano (Milan) has moved to Spain now has it? Amazing what those idiots in Brussels will do:D

[David B.]

David there are lots of these around:

 

http://www.ebay.co.uk/itm/Gunson-77111-Tuning-Spark-Plug-Cleaner-Tool-Garage-Auto-/330832876563?pt=UK_Hand_Tools_Equipment&hash=item4d072d1413

 

Gunsons seem to have started to produce them. For ages the only ones advertised were in the USA with high carriage costs. For some years I have been using a "Wally" from Italy it leaks grit a bit round the top were the plug goes in, hence these new ones have a shroud.

 

Only blast for the minimum length of time to minimise the damage to the insulator.

 

I always used to regard a blasted plug as being as good as new, but this is not the case it will require more HT to get a spark unless the contacts are filed & reset. Although that may be difficult with a multi contact plug.

 

Thanks Clive - looks a worthwhile buy. Presumably under the bag its much the same as your "Wally"

[Tony B]

I seem to remember a gadget with a circular brass brush. You shoved a plug into the middle and twited it about. Worked very well, do they still exist?

[fv1609]

I seem to remember a gadget with a circular brass brush. You shoved a plug into the middle and twited it about. Worked very well, do they still exist?

 

Tony I'm not sure how that would work because of the interference with side contact. I think you have two things in mind.

 

There are thread chasers for sparking plug threads. There were narrow wire brushes for poking & twisting up the sockets of caravan connectors, were you thinking of those perhaps?

[Tony B]

Tony I'm not sure how that would work because of the interference with side contact. I think you have two things in mind.

 

There are thread chasers for sparking plug threads. There were narrow wire brushes for poking & twisting up the sockets of caravan connectors, were you thinking of those perhaps?

 

No not that one, I know the gadget you mean. This was a semi circular block with a hole in the middlle. The hole had brass brushes around the edge and the bottom. You held it onto the bench, or may have been clamped, the plug was pushed into the brushes and spun about by hand. It was a simple little tool but worked well. I'll see if I can find a picture on the web.

[Big ray]

I have had this plug cleaner for so many years that I have forgotten where I purchased it from, its an A/C and it works brilliant.

[hoppy]

Your plug looks to be "sooted up" from running rich for short intervals. The choke is intended to make the mixture ritch thus the soot.

 

You are doing your engine a severe disservice by running it for short intervals in the winter. Look at the exhaust pipe of a cold engine running & you will often see water running out the pipe. If you must start the engine it is wise to run it up to full temperature to evaporate as much of the water created by condensation on the cold internal parts. Otherwise the water just stays in the combustion chambers & can cause great corrosive damage. ( It is illegal to start a piston engined aircraft in storage without running it up to full operating temperature. Failure to do so can result in a major engine overhaul demanded by the MOT. )

 

Much more advantage in preserving an engine in storage can be accomplished by disconnecting the coil wire & turning the engine with the starter once in a while. This will distribute oil where it is needed but will not cause the condensation previously described.

 

In the spring remember to re-connect the coil wire --- I will not publicly admit to why I suggest that!

 

Many thanks

 

Just an update the plugs were cleaned, vehicle taken out for about a 5 mile run but the plugs were once again quite balck, I ve added a few photos of the carb, the garage stank of petrol once back in so I think the issue is there somwhere; thoughts about a rebuild of the carb. Is it a straight forward job. Does it just need a good tune up and a bit of TLC instead.

 

Cheers

[paulbrook]

It's just a thought - but if it was running fine after 5 miles there can't be a lot wrong with it. If there is a very strong smell of fuel its much more likely to be a fuel pipe or connection or a weep around the fuel pump diaphram.

 

In any event running a bit rich is far better than running a bit lean (ask any exhaust valve).

 

Has anyone ever used a Gunson Colourtune on a jeep engine?

[Pete Ashby]

Has anyone ever used a Gunson Colourtune on a jeep engine?

 

Yes I have on a number of MB, GPW, Dodge, Chev and GMC engines from new rebuild to tired out. On a new engine and carb it can give useful results. On a tired engine and worn out carb it's not reliable as the adjustments have to be large before any real effect is seen at the plug.

 

Pete

[Tony B]

BUT! How's it supposed to work?

[Pete Ashby]

BUT! How's it supposed to work?

 

It's very simple Tony, it's just a replacement plug with a toughened glass screen so you can look into the combustion chamber and monitor the colour of the fuel air mixture as it burns. This is then compared against a chart, there are claims that you can diagnose all sorts of ills, personally I have only ever used it to set the idle jet. The problem is that with 70 year old engineering practices tolerances are not as close as with modern systems also the specification for military carburetors is designed for power not fuel economy and this can skew the results particularly with accelerator pumps that just pour fuel by the bucket load into the engine as soon as the throttle is opened.

I'm not sure if they are still available I've had mine for years along with a 14/18mm adapter. In short it can be useful if used with the above in mind but can be misleading if too much is read into the results :nut:

 

Pete

[Pete Ashby]

Hoppy, looking at your photos you posted it looks like you have a Solex carb fitted? are you sure it's jetted correctly for your engine ?

 

Pete

[Tony B]

It's very simple Tony, it's just a replacement plug with a toughened glass screen so you can look into the combustion chamber and monitor the colour of the fuel air mixture as it burns. This is then compared against a chart, there are claims that you can diagnose all sorts of ills, personally I have only ever used it to set the idle jet. The problem is that with 70 year old engineering practices tolerances are not as close as with modern systems also the specification for military carburetors is designed for power not fuel economy and this can skew the results particularly with accelerator pumps that just pour fuel by the bucket load into the engine as soon as the throttle is opened.

I'm not sure if they are still available I've had mine for years along with a 14/18mm adapter. In short it can be useful if used with the above in mind but can be misleading if too much is read into the results :nut:

 

Pete

 

Thanks, seen them for sale but I've never had one.

[hoppy]

Hoppy, looking at your photos you posted it looks like you have a Solex carb fitted? are you sure it's jetted correctly for your engine ?

 

Pete

 

Pete

 

You are correct Solex carb is fitted. Being a novice and most of my work is done via mauals and the like how do I check that it is jetted correctly?

 

Many thanks

[Pete Ashby]

Pete

 

You are correct Solex carb is fitted. Being a novice and most of my work is done via mauals and the like how do I check that it is jetted correctly?

 

Many thanks

 

Hoppy for your jeep I think you should have a Type M32PB1C Solex however I have seen other Solexs plonked on instead... for some reason jeeps seem to attract odd carbs. From what I can see in your pictures yours looks right but worth a check.

Do a search on this forum for 'Solex Carbs' I think this topic has been discussed before. If you still have an issue with running rich I'd think about a rebuild kit for the carb assuming you have the correct model.

 

Pete