Hello,
I've previously had a problem with pinking and running on. I took your advice and retarded the timing and that sorted out the pinking but I still had occassional but not too drastic, running on problems. I thought it was due to the lead replacement additive I was putting in when I filled up because it didn't seem to do it when I didn't put it in, coincidentally.
However, I have now fitted an unleaded head and it seems to be just the same if not a little worse...how can this be? I would be grateful for your advice as I know it isn't good for an engine to run on and would be very happy to get the problem sorted out.
Yours in anticipation....
Guy<br><br>
Doesn't do the engine any harm to 'run on'. It's caused by something glowing red in the combustion chamber - and that keeps the fire going after you have switched off the ignition! Advance the ignition slightly until you get a little pinking - then reatrd it very very slightly. You've then done all you can with the timing. Drop the idle speed as low as possible - and set the mixture up correctly. Have a look at the spark plugs - what make/number are they ? Lastly (or perhaps should be firstly) - try a different brand of petrol!
Wasn't there a thread on the forum a while ago about either spraying water mist into the carb or adding a bit of diesel to a tank of petrol to get rid of the carbon in the head?
Personally I think running on sounds horrible and would want to be rid of it if I had it
This is a supposedly 'unleaded' head - presumably recently fitted - so unlikely to have significant build up internally. It's likely running retarded/weak - and the tip of the spark plug is glowing red!
The head was well coked up when i took it off, which I thought could be one thing contributing to making it run on. The plugs were more black than coffee coloured, but that was due to it running a bit rich which I have now sorted with a new needle and jet and a bit of tweaking.
The new head was, as one correspondent has already pointed out, coke free, so its not down to that now.
I haven't checked the plugs again for colour but will do when I've had a bit more of a run as I cleaned them up when I fitted the new head.
I've only done maybe 10 miles in it since the new head was put on but the running on was considerably worse than it had been before! I have a good long run to do today and it will be interesting to see how it performs later on.
Perhaps I should advance the timing a bit, and see if that helps.
I'll let you know how it goes.
Advance till it pinks - then back off v slightly! Were all the sharp edges carefully smoothed off in the head before fitting ? What exactly is the history of this head - where did it come from ?
Well the good news is I advanced the timing a tad and she's going like a rocket now and not running on even after a steep hill climb up to our house, which was when it usually happened.
So thanks evryone for your comments and advice, another problem solved with a small amount of effort and no expense!
One other thing,...how come evryone elses photos are of a similar size and mine is enormous!!? Have I not done something properly when up loading?
Cheers!
Looks to me as if you added the picture in the message. Everyone else's pics are part of their signature. You can add a pic to your signature in your profile settings.
Matt Coles Young Members Registrar
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Glad you got your problem sorted