850 Ultra XP lean bogs when secondaries open

Thanks Demonx2 I will look into that.
I know it seems obvious, but not mentioned, are the fuel levels on the nuggets? If the level is even little low on a combo prone to a weak low-speed signal, the mains will be too slow to start discharging. Just a thought, I've rarely found one correct frt & rear after being shipped, if it hasn't been outright damaged..