Right.... Turned out that the rod device attached to the choke diaphragm in the refurb kit was slightly the wrong size for my carb. Hence, it wouldn't re-start as the choke wouldn't fully shut. Took ages to find this, during which I ran out of bloody petrol, which may account for the flat spot, or it may be to do with the choke, I suppose. Please don't repeat my schoolboy error and forget to re-attach the fuel line, dousing a hot engine bay with petrol. Anyway, after I'd changed my trousers, replaced the clagged-up fuel filter and allowed the petrol to evaporate it re-started and seems to be OK now. I need a drink.
Bought an old VW Solex PICT34 -3 in Tatton Park yesterday. (Trying to remove a stubborn flat spot). Stripped it, cleaned it and fitted it. Started first time, but my joy was reduced when it died as it warmed up and refused to re-start until it was cold again. Choke appears to be doing its job. My overnight thoughts are: either the idle screw needs to be turned out further or I have a blockage in the idle circuit. Any additional/better ideas please? Mark.