Holley 2280 throttle bushings

Bewy said
I doubt 0.003" of wear is causing any problems. You have an adjustable air+fuel supply [ the mixture screws ] to compensate for variations. That is why it is adjustable.
I tuned my first carb in 1964 & I am still learning.....
I never use a vac gauge for idle adjustment, I tune by ear & feel. You want the highest idle rpm combined with smoothest running. Squirting propellant around any gaps WILL increase idle speed, that is normal.
Getting back to shaft clearance & air leaking past it. There are numerous sources for the air entering the engine at idle:
- PCV valve
- gap around t/blades
- air past idle mixture screws
- the t/slot; air from above the t/slot, around t/blade, exiting on the manifold side.
- leakage past the t/shaft.
So leakage past the shaft is only a small proportion of the total amount of air entering the engine at idle.
I have not found the hand-over-the-carb test very useful & I do not use it.

-I guess i could try plugging the PCV port on the carb. it is hooked up to an early valve cover with the ribs that doesn't have the modern PCV with the grommet. it has a bent tube of metal with a check ball inside.

-Is there anything that can be done about the space around the throttle blades? I did notice some slight light coming through when i put the shaft back in

-no sure about the t/slot or how to check it

-would adding an o ring between the carb base and throttle linkage and another on the opposite side with a washer and small spring help with throttle shaft leakage?

I can get it to idle at 750 but it's no were near as smooth as the 1 barrel carb. the 1 barrel carb I could get to idle at 500rpms but couldn't get any lower because the curb idle screw wasn't touching anymore.

It still seems to be running rich as my eyes get itchy after running it in the garage with the door oepned and strong fan circulating air. it also stinks too