1050 ifr sizing

[Steven's]

I've got an older 3 circuit 1050 annular booster dominator that I converted to a 2 circuit with qft metering blocks several years back. I run the ifr's in the low position and had tuned it with .040 ifr's and .056 t-slot restrictors with 75 air bleeds. 77 main jets 28 bleeds. Locked timing, 12-1 on sunoco 110 , iron heads. I hadn't run the car for a couple of years, and when I test drove it, the t slots were way rich. So I jetted down like 5 increments and ended up with .035 t-slot restrictors. Ran fine, but still rich in certain lower throttle positions. So I dropped the ifr's to .035 and tried .050 t-slot restrictors. Still rich, so I dropped the ifr's to .033 and it's pretty decent as far as seeing some upper 14's on the afr.
At first I thought the a/f gauge might have been off, but I recalibrated it, and it read the same. Then checked to p/v gasket, which is good. Metering block gasket is good as well. Anyone else ever have to run that small of ifr on a 1050 4500?

[Zoompala]

How big is the motor?

[GTO Geoff]

You are under a common misconception: that the IFR is sized for idle. It is NOT. The IFR supplies the T slot, with the T slot being the transition cct from idle to main cct. So the IFR is sized to provide the correct A/F ratio for transition.

[Steven's]

I fully understand that the ifr's feed the transition slots. My question is if anyone else has ever experienced a situation where they had to use. 033 ifr's on a 1050 to get decent t-slot afr's.

[Steven's]

[Zoompala]

I'd say .033 to .035 is about right. How many turns out are your idle mixture screws? Should be around 1 1/2, if lower than 1 I'd say you need less if over 2 I would say you need a little more.

[Steven's]

1.5 turns out. The idle afr doesn't change between .040 and .035 ifr's, with the screws set the same. But did go up a tiny amount with .033 ifr's.

[Zoompala]

Perfect, any hesitation from idle?

[Steven's]

No. It's got 50 cc pumps, and timing locked at 35, so it's got stupid throttle response everywhere. There aren't any drivability issues with any ifr I've tried , yet... it's more the issue of not wanting to soot up the plugs, waste fuel, and stink.

[jmarkaudio]

My thought is a fuel leak at the PV or PV plug gasket.