Sorry Brian it is 2007, I just Googled Zenith 22FZB carburettor and found the thread almost immediately.

Brian, the Viton "O" ring shavings gives the clue that you have recently been tinkering with the petrol tap. This being so, one of my first checks would be that there was a sustained, adequate flow of fuel to the float bowl??

Ian Mc.

Location: Shropshire

I'm very grateful for the suggestions and decided to ensure that all the joints are flat. I've had the exhaust manifold on the miller for a light skim both sides, the problem here was pitting corrosion.
The carburettor faces were check but only needed a light linish.
The inlet manifold I had thought was good but examination revealed that, whilst a check along it indicated no problems, a check across the carburettor joint faces showed considerable errors which a couple of hours of hand sanding with a piece of sanding belt glued to my surface table has improved it no end it could do with another one with more metal on the faces.
I'm now getting ready to reassemble and picked up a NOS tube of Holts jointing compound at Wollaton to assemble things with. I had a smell of it and it has the same smell as 'Osotite', of which I have a small can in the workshop. The stuff I have been using was like Blue Hylomar but does not stay flexible, despite what It says on the tube.
I 'll let you know how I get on.
Brian

Location: Near M1 Motorway Jtn 28

SUCCESS!!!! Many thanks to all on and off this forum for help and advice. The car started on the first swing of the handle today and just needs some very minor adjustments to make it run really well.
The worst out of flatness on the inlet manifold was underneath where it was very difficult to place some thick oil to see if that revealed the leaking air. Just need a longer run to satisfy myself that all is well and then a short run on Saturday or Sunday to the Belper Steam Fair near Denby in Derbyshire, might even be the odd Austin.
Brian

Location: Near M1 Motorway Jtn 28

Well done Brian, glad you got there in the end

Location: NZ

Maybe I'm unlucky but every Seven engine part that is supposed to have a flat mating face that I've come across is anything but flat. Crankcase top faces are the worst usually exhibiting fretting damage from loose blocks and or starter housings, while every exhaust manifold has had a distinct hollow in the centre. So it is has been standard practice to check all mating faces before use.