I doubt whether the secondaries are causing the bog issues , air speed needs to be pretty high in order for the secs to open regardless of spring tension , i can't see they are opening when you hit the gas from a standstill , get hold of a paper clip & wrap it round the secondary arm , go hit the throttle till the motor bogs then go see if the clip has moved up from where you placed it , this will answer you're question , good luck.