Restore job. She sounds and runs great.Except no power when u hammer it,and small sputtering backfireing when u let off the throttle.I synchronized the cards by the manual.No change HELP?

Sounds like fuel starvation to me, or there maybe a hole in the diaphram on the 2nd carb.

 

TTB

if I,m not mistaken theres a filter gauze attached to the float needle valve seat, check its clean. If it's mucky it will give those symptoms.