[hammetrulzesp]

Hey Guys!

We were rebuilding my Rochester Quadrajet 4-Barrell carb and when we took out the Lean Mixture Adjustment Screw without remembering to count the amount of turns for indexing how it was set. Does anybody have any info on how these were set from the factory? Don't wanna spend $350 on a new carb!!
Thanks so much!!

Chris

[johnsongrass1]

3 turns from bottom and readjust when the engine starts using a vacuum guage.

[hammetrulzesp]

Thanks for the reply. After I set the screw, where do i place the hose on the gauge to check it?

[troy-curt]

Every one has there favorite way to do things that they do every day. Most will get the same results.

I start at 2 turns, then use my ear. or a tach.

Troy

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[docvette]

Doc Here

The most simple way to Adjust the Mixture Screws on an Q~Jet (And Many others)

Is Carefully turn them all the way in.
(don't jam them or they'll leak)

Then back them out 6 half turns.
(3 total turns)
Then Start The engine.

Adjust for Absolute Highest Idle.
(Turn slowly and listen Carefully This may take a lot of time going from left to right and back again)

You Want the point at which Highest Idle Begins, With No Stumble or Miss ... Smothe high idle.

Check the exhaust for raw fuel smell as you adjust You want the minimum Smell From there.
(You may not be able to get rid of it all with just the Idle Screws, so just the minimum will serve)

After You Think you have it right, put a Vacuum Gauge on any Non~metered Vacuum Port or manifold and set for highest Vacuum At Idle about 17 to 20 Hg Depending on your engine, and on Rev, should Drop to about 5 To 10 Hg and return.
(You Should be on or at that spot with the higest idle setting anyway.)

That Should Do it!

Regards,
Doc