Main Air Bleeds (HSAB) - 1850-3 carb

[novadude]

Got one on the bench now that has the PMAB @ 0.031, and the secondary @ 0.028. Seems a bit large from what I've see others share that are using "600" cfm 1.25" / 1.313" venturi carbs with straight leg boosters. Should I reduce these to something more like 0.028" Primary and 0.025" secondary, or am I still in the ballpark using what I've got. I'm assuming the large HSAB will lean the top of the curve, but I am more concerned about the effect when the mains first become active. Will too-large PMAB make it a little rich at the transition?

The rest of the calibration (stock) is as follows:

PIAB: .063" (will likely open this one a bit to 0.067-0.070)
PIFR: .026"
E-holes (primary): .028"
Kill bleed: 0.028 (up high in dogleg - plan to block)
Primary jet: 65
Secondary plate: #39
SIAB: .028

Not sure if I need to reduce those HSABs? Any thoughts?

Thanks!

[GTO Geoff]

Larger air bleed will delay the start of the cct because it weakens the signal.

[HarrysTaxi2]

[novadude]

[CDN]

I always thought smaller mab delayed the circuit my HP 1000 came with .025 with .075 iab now .028 with .070 iab

[novadude]

[CDN]

yes Novadude thats what believe you said it better
Im trying to lean out my cruise and my thinking is going to larger iab 75 and smaller mab .025. will help over rhe current .070 iab .028 mab. carb performs excellent with current set up but cruise and tip in is rich
Not sure if im thinking right but gonna try my ifr is .035 bottom wondering if ishoyld change that to .032 but assume play withbleeds first ?

[RFSPHPbb]

what size engine? overall rear gear? what is the steady state cruise RPM? do you know if the main system is functional at that RPM? if you're cruising on the idle transfer slots changing the jets or main air bleeds isn't going to make much difference.

look down the carb with good light, slowly bring the RPM up to the cruise RPM, note the boosters. are they operational? solid white fog in them? not just dripping? at some RPM level they will be working, swamping out the transition circuit. above that RPM you will be tuning with the main jets and MABs. below it you're on the idle transition circuit. you will be tuning with the idle fuel restriction and idle air bleed.

Do you have a WBO2 hooked up and working?

[novadude]

[Right hand drive]