Cliff's Quadrajet Parts and Rebuild Kits

Quadrajet Problem Solving => Dialing in your rebuilt Quadrajet carburetor => Topic started by: novadude on November 07, 2013, 06:52:07 AM

Title: Setting idle mixture screws - vacuum gauge or tach?
Post by: novadude on November 07, 2013, 06:52:07 AM

I generally use a tach and look for highest idle speed, turn screws in until idle just starts to drop, than back out 1/2-3/4 turn.  I've heard others say that using a vacuum guage is the best way to go.  What method do you guys generally use?

Title: Re: Setting idle mixture screws - vacuum gauge or tach?
Post by: Cliff Ruggles on November 12, 2013, 03:56:48 AM

I set the screws for highest rpm's, then slowly turn them in until I notice a slightly speed change or change in exhaust note (going lean).  Back them up about 1/3 to 3/4 turns each from that point.  You are setting them right on the edge of "lean tip-in".  This will be the best place to set them for most applications.....Cliff

Title: Re: Setting idle mixture screws - vacuum gauge or tach?
Post by: Schurkey on November 22, 2013, 09:38:10 PM

My experience has been that a vacuum gauge is far more sensitive than a tach.

Try both...see which one you like better.