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Hello Gentlemen,
This is the first time posting on the forum. I have a 66 tripower GTO. All is fresh and stock. The carbs are running a little rich. The mechanical adjustments are good. What is the proper way to set the air fuel mixture using screws on center carb?
 

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Best way is to use an air/fuel meter, like one of the Innov8 units. They're pricey though. Next best in my opinion is to use a good quality vacuum gauge and adjust for peak vacuum at idle rpm. It'll be an iterative process, because as you sneak up on the setting it's going to also change rpm somewhat, so you'll want to keep adjusting rpm too.

Bear
 

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64-67 Expert
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What Bear said. You can simply warm the engine up, and start turning in one screw at a time a very slightly until the engine stumbles, and then turn the screw out slightly CCW until the engine smooths out. That's how I've done it forever, and when it's plugged into a 5 gas analyzer, I'm always on the money......but I'm pretty experienced doing this. If it's rich off idle, you have other issues, like float levels, jetting, etc. I've run several tripowers on several cars over the years, and they are much more effective and reliable than most current technicians like to admit....the original unit is on my '65, and last time I rebuilt it was 30+ years ago. It looks very, very grungy, but works great!
 
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