What size is the IFR? I would think it needs to be about 0.038- 0.040", possibly bigger.
Contrary to popular belief, if the IFRs are smaller than above, enlarging them will NOT make the idle richer. If the t/blade position is correct relative to the T-slots, the idle mixture gets adjusted with the mixture screws. Enlarging the IFRs will richen the T slot cct to help with off idle tip in. I am not sure if QF uses a restrictor/restriction to the T slot; often called the IDC, idle down channel, it supplies mixed fuel + air [ volume ] to the T slot. It may also need enlarging, & I would enlarge a minimum of 0.005".
Two other things you could try. A smaller IAB. That will help the idle cct activated higher into the rpm range. A smaller MAB will bring in the mains system sooner to pick up from the idle system tapering off.
Contrary to popular belief, if the IFRs are smaller than above, enlarging them will NOT make the idle richer. If the t/blade position is correct relative to the T-slots, the idle mixture gets adjusted with the mixture screws. Enlarging the IFRs will richen the T slot cct to help with off idle tip in. I am not sure if QF uses a restrictor/restriction to the T slot; often called the IDC, idle down channel, it supplies mixed fuel + air [ volume ] to the T slot. It may also need enlarging, & I would enlarge a minimum of 0.005".
Two other things you could try. A smaller IAB. That will help the idle cct activated higher into the rpm range. A smaller MAB will bring in the mains system sooner to pick up from the idle system tapering off.