finally got new 6pak setup and idling smoothly. when i turn in the center mix screws to try to get it to stumble,no change? i only ran it for a minute or so,so it didn't get to oper. temp. is this my problem,or do i need to take my new carb apart? thank you,as this has become a frustrating project.

Yes you need temp in the motor. The fuel burn characteristics will change once heat is in the intake and runners.

once the engine is warmed up and if you still have the same situation with the idle mixture, you may have to lean out the outboard carbs to give adjustability to the center carb.

thank you for helping,new to the 6pak world,found i had 1000rpm was into transition circuit,lowered to 800,aloud to get to temp. all good