I don't think you can adjust your way out of it. To me it sounds like that the ratio between air and fuel is not right. I would remove the carby, strip it and clean it with carby clean maybe soak it over night. Maybe some of the tiny canals are partly blocked. Blowing air through does not help. Do you see any white sediment inside the carby? When cleaned, blow air through and set the mixture screw to factory setting, 6 turns from home and when at working temp. adjust from there.
Happy working

I have already stripped and cleaned the carb, there was no dirt in it at all, not even fine, it has had a fuel filter on since 83k and now on 113k with various replacements at services. mixture has never been adjusted so I am struggling to see why she may be running badly all of a sudden?

I will let you know how she is from cold in the morning tomorrow.

I think screwing the mixture screw inwards will weaken the idle mixture, so it might be worth screwing it out a bit further to see if that makes any difference? Especially if richening it by putting the choke on seemed to help?

Not got a picture of the idle jet, but it's the 8mm brass nut with a screw slot in it on the front of the carb. The one on my Dyane kept on getting blocked for ages after I got it, so it might be worth having another look at it? I've found sometimes that just blowing it through wasn't enough, and I've had to gently clean it out with a strand of wire.

Could possibly be an air leak in the manifold somewhere? Is it running fine the rest of the time?

Dirt enters carb in the air stream. Classic case is an old, unserviced filter which is beginning to disintegrate. Often carb removal and a squirt of air up the wee air hole on the underside is required. Maybe running badly all of a sudden because all of a sudden, a speck of dirt has entered and blocked an internal gallery !

Not sure about the quality of current air filters - they don't look great to me. Bought a better one for a bit (£12 ish) more, MAN I think - looks much more like OE standard.

So.....?

Didn't Tim mention checking 'something cheap or free' on FB?
Whatever that is, it seems to have done the trick, so he may need to make room in the spares box for the new yellow coil, new plug leads and new 123...

The problem is sorted, as Ken says it didn't actually cost anything to fix. Although in reality it cost a few quid!

I'll leave it to Timmy to give us the lowdown, as he's promised to fill us in!

he should think himself lucky it wasn't on points, it'd have a new engine by now...

ok, what a div i have been.... short story is that the bolts on the inlet side of the manifold spider were finger tight for some reason. Its amazing how many people you tell then they say, oh yeh, i had a car do that too... why didnt you say before i bought some of the most expensive spare known to man! never mind... tightened them up and what a difference!

D*lly is back to her happy little self now!



Think I made a boob today, didnt notice the speed cameras as I was excitedly racing past everything at full chat... until i went through the first one 20mph too fast! Fingers crossed I wont have to pay for an ace picture!

Tim,
Luke and I did try...

"Could possibly be an air leak in the manifold somewhere? "
&
"The best test I've found is to use a small plastic oil can to drip petrol directly onto suspect areas, which include the intake manifold to head joints as well as the carb base."

ken.