Stewart - please excuse me if I'm going over old ground for you, however check butterfly disk orientation and alignment - in either or both of your carbs - as one mis-aligned disc will cause high revs in the balance of the plunum (manifold) chamber. Butterfly discs have a bevelled / angled chamfer. Also check the alignment of the discs is central within the chamber before tightening the set screws. Any small measureable gap will not lend itself to proper idle adjustment. If you do have the carbs off again, check for misalignment / gaps with a torch through the body chamber.

You mentioned no reading on your vacuum gauge - this could also point to an atmospheric leak somewhere within the circuit.

Let us know how you go

Thanks for the suggestion, it's on the list of things to do I will certainly put up a post when I finally solve the issue. It's bound to be something simple that my mid seventies brain is missing.

_________________
Mk 1 Cooper S 1965
If you could erase all your mistakes of the past
You would also erase the wisdom of your present
Remember the lesson not the disappointment.

Hi, just to let you know I haven't had chance to get back to the issue at hand, sometimes other things take priority, I'll up date any progress when I have time.
Thanks for your suggestions Stewart

_________________
Mk 1 Cooper S 1965
If you could erase all your mistakes of the past
You would also erase the wisdom of your present
Remember the lesson not the disappointment.

Hi,
Thanks to advice from a forum member, my problem is resolved.
One of the manifold locating rings wasn't seated correctly, preventing the inlet manifold from sealing completely, even though the nuts were tight.

Many thanks to everyone that assisted me.
Stewart

_________________
Mk 1 Cooper S 1965
If you could erase all your mistakes of the past
You would also erase the wisdom of your present
Remember the lesson not the disappointment.