Fired up the old rustbucket for the first time a couple weeks ago, started playing with the tuneup a little bit.

On my 4150 Race Demon (it's the downleg booster one rated at 1000cfm)I noticed I get the best idle quality with the secondary mixture screws about 1 to 1&1/4 turns out which seems fairly normal (from past experience).....but the primary idle mixture screws have me weirded out a bit.

Best idle quality/vacuum/rpm is with the primary mixture screws only adjusted out about 1/2 to 3/4 turn.

Assuming float level is correct, wouldn't that indicate a need for smaller or larger low speed air bleeds? Or am I overlooking something?

Thx