At wit's end with carb

[robert ray]

I have removed my carb twice and carefully cleaned and checkedjets, float valve ect. It will only run with the choke on full and will only respopnd to about 20% throttle open. I have a fixed main jet, which way richens the mixture ? The engine is newly rebuilt and has great compression. The mechanical fuel pump is fine. How long does it take to empty the bowl as you advance the throttle. I checked for vacumn leaks with carb cleaned no luck.
it must be starving for fuel but how?