Rhys,
Far be it from me to argue with you about carbs, so that's not my intention here. But it seems counter-intuitive to me that; if he has to make 2 or 3 attempts at full choke to get the thing started and that it runs smoothly when the manifolds have warmed up, but the thermostat is still closed, and he then has to feed choke to keep it running smoothly when the whole engine is fully warmed up; he's running rich. I would have said that he is running lean. I'd appreciate your setting me straight on this, so I'll know which way to go if this were to happen to me.
Bob S.