Fitted New weber

Ive just fitted a weber carb too my Mk1 but having problems with it.
Its running sort of ok but when i give her a few revs she starts holding back then when i go on a motorway she starts losing power and cuts out. Please can anyone help me with my problem thanks micky.

Did you follow the instructions with the carb to set up the best lean idle?  If not, you need to do this.

 If you DID set up the carb for best lean idle then you'll need to go to your nearest friendly garage and ask them to set up the CO and idle on a gas analyser. Shouldnt be more than £20 ; )

 hope that helps!