The connections I made were rubbish! When I checked again it was retarding rather than advancing. But - on these carbs there are balance ports and some time ago when I first had a go at fitting them I made up a "manifold" in hard plastic pipe with push connectors so that three of these ports are connected to the vacuum advance = result, much better, as long as you've renewed the o ring seals for these ports. The take off above the butterfly now just serves the emission valve and all seems well again.