Misfiring and backfiring

Hey everyone, just replaced my exhaust and manifold, so thought I'd take my carburettor to the garage for a clean etc. I've got it all back together now and it runs really nicely when idling, but it's be difficult to start without closing the choke, and misfires really badly when I open the throttle (almost dies initially and backfires a lot as the throttle opens).
I've been adjusting the mixture on the carb but I don't think it's to do with this because as I say it's idling really nicely.
Really want to get it running smoothly but I'm out of ideas really. Any suggestions would be very welcome.
Cheers.

I'd guess at an air leak somewhere. Did you renew the manifold to head gasket and the carb to manifold gasket? Did you replace all gaskets/seals/o-rings on the carb when you stripped it?

Yeah replaced all gaskets. I guess it is possible a little bit of one of the old gaskets was left on or something, might be worth looking into. Cheers mate.