Topic: Holley Idle Circuit Adjustment

[hopey]

Angela,

Id suggest Drew Pojedinec at AirFuelSpark if you are still looking to get that carb working. It could be any number of things, often even new components are incorrectly machined. I had a BOSS carb that Joe did for me several years ago and I could never get it to run well, even though it looked fantastic. I sent it to Drew, who went through it and blueprinted/re-checked everything, found a couple issues. It runs great now.

[Drew Pojedinec]

Her carb has mixture screws in the baseplate as well as metering block.
It was running lean the whole time. Sometimes those baseplate screws reduce fuel too much.

When you put an engine in gear it swings lean.
This stalled the engine.

This is why you set mixture at idle in gear with an auto. With a manual you set no load and richen a bit from there 1/4 turn maybe.
My advice would have been to turn the mixture 2.5 turns out from seated and go from there. Turn in 1/4 turn and test. Turn 1/4 and test.
There is also the possibility that the ifr had some trash in it.
390GT carbs are more irritating than most, her issues are common. Moreso when people install aftermarket camshafts.