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Hi

 

I was out on a short run the other day and could not help noticing along with a lot of the local population that I was getting a misfire.

I checked the plugs which had a bit of carbon build up which sugested too rich a mixture. I adjusted the setting to a weaker mix and cleaned the plugs. The engine was still idling a bit rough and prone to misfire when I give it a bit of gas. After 15 minutes idling in the garage the engine note changed to something much more acceptable and now its running sweet as a nut.

The questions are....did I fix it? did it fix itself? might it come back?

 

Keith

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Life's too short.

 

Mick Richards

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Hi Keith

 

I have a similar issue, particularly after the car has been idling in traffic for any meaningful time.

 

The carbs have been fettled as much as their olde state allows without a full rebuild, electrics checked and leads replaced and plugs cleaned renewed replaced far too frequently.

 

I was advised that because the state of tune of my engine, it is an inevitable consequence of slow traffic and the plugs fouling quickly. Do you have a particularly fasty road set up?

 

I find that after suffering heavy traffic queues, as it misfires in #gear at #mph, I have to drop down a gear, get the revs up significantly and speed up to clear out the misfire, then when I go up to the next gear, I have to do the same, all the way up through the box (which doesn't take long when you only have 4 !); after which it doesn't seem so bad. I am not sure if the high revs partly clear the plugs or whether it just stops the carbs from drowning !

 

However, when you don't have a clear road or the stationary traffic is considerable, as is the case with most motorways these days - it can be a real nuisance.

 

Olde Smokey certainly lives up to her/his name - glad I don't have to sit in traffic behind me !

Edited by McMuttley
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"The questions are....did I fix it? did it fix itself? might it come back?"

 

No. Yes. Yes. (probably)

 

There isn't much point in asking questions like that Keith unless you also give some background e.g. what state your engine is in, standard or tuned, and what bits might have been altered like electronic ignition etc. Is this a one- off did the car run OK until this happened; do you drive the car regularly, when did you last fill up.........and so on.

 

There are a million-and-one things which could cause the symptom. Just make sure the fuel system and electrics are A-OK and use good fresh petrol. The fact that it cleared after idling for a long time might indicate its something to do with heat (or lack of it) as everything including the carbs would have wamed up nicely. If the plugs consistently foul up with the correct mixture, try a hotter grade of plug.

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If you have fixed it well and good but unlikely that it fixed itself.

Worth doing the following

Grasp the plug as it goes into the plug cap (not distributer cap at this point) and give it s pull to see if it is fully home and tight.

If using the twist onto pointy threaded screw, try tweaking them up a bit.

 

I just had the problem you describe at the weekend and only manifested itself under acceleration and disappeared when I backed off the throttle. Checked all electrical connections this morning and then went through the above procedure. Number lead was only connected by touch so screwed it back in and Uncle Bob is my mine!!!!!

 

A worthwhile check at any time particularly with some plug lead types. I use competition wire leads with NGK caps which screw onto the central wire not the synthetic type which I juist do not trust.

 

Simple tips can save hours of time and cash. The obvious isn't always!

 

Rod

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Hi Roger, I did suspect that heat may be a 'contributory' factor.

 

I am awaiting another one of those rare Sheach HS6 heat shields (for a 4FRE engine with dirty great rally exhaust - hint) to come to the mkt - missed one last year !

 

In the meantime the fuel lines are wrapped in heat sleeve (thought I might as well try) and I have a revotec tube directing air from cowl to the carbs - although the latter is of little benefit when not moving.

 

The problem is that after a slow traffic event, even the next morning the same occurs, thus my assumption that the plugs are fouling and needing to be flushed clean with some revvvs/speed?

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I had hoped that the preacher man who designs carbon fibre bits for red bull (a friends father) would do one for me, but the complexity of creating a template meant the budget would only suit an italia owner !

 

That said, I've seen your hourly rate - could be close !

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I had hoped that the preacher man who designs carbon fibre bits for red bull (a friends father) would do one for me, but the complexity of creating a template meant the budget would only suit an italia owner !...

 

Perhaps there are some scrap Concorde parts you can use?

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