Jock,
Let's check the obvious first. I'm sure there will be more useful replies besides mine coming in.
1) Check your choke cable assembly, make sure the choke is fully closing after start-up and the tab is touching the stop peg on the housing.
2) If you disassembled the choke mechanism and disc, make sure you have correctly repositioned those parts and the index marks are in the correct location.
3) Check your mixture screw setting.
4) Make sure the mixture jet o-ring has not been torn or pinched during reassembly. I like to use the slightest smear of silicone grease on the O-rings. A very small amount, just a smear. Turn slowly when removing and re-installing.
5) Are your metering needles set at the same and correct notches?
-Mike V.