Tune carburetor

[Huicho417]

Should the idle mixture screws on a edelbrock carb be adjusted with car in park or drive ? I am using a vacuum gauge to adjust for highest vacuum reading. Car is a 67 coronet with 318 and automatic 727.

 

[AR67GTX]

Seems like some manufactures might have called for adjustments in drive - but don’t bother. Adjustments in neutral are good enough. Besides it saves you the embarrassment of doing what I did one day when I was about 20. I was setting the idle speed in gear in my 64 383/Torqueflite Sport Fury. Leaning over the left fender with my feet straddling the tire, I adjusted the engine rpm and then with a complete lapse of thought, I grabbed the throttle arm and gave it a quick yank to clear the engine. Engine went wompt, front of car jumped up, and front tire rolled over my left foot and stopped against the curb. Thanks to weight transfer I hardly felt it. I was more embarrassed that someone had seen me do this stupid stunt and quickly looked all around. Fortunately not.

 

[lewtot184]

If you're using an automatic choke carb the mixture screw on the passenger side will be out more than the driver side.

 

[Don Frelier]

If you're using an automatic choke carb the mixture screw on the passenger side will be out more than the driver side.

Please explain?
At idle the fuel level should be equal on both sides of the bowl.
Fuel comes in on the passenger side so if anything I would think the opposite.
I've often found that one side would be more responsive to mixture screw changes (not sure if it's the carb, intake port arrangement etc)
But I would usually use the more sensitive one as a base setting and then match the other mixture screw to the same number of turns.
I would then try a quarter turn more lean on the non responsive side and and retune with the "better" side.
In the end I always go towards a more lean setting.

Back to the nuetral vs drive setting I agree not much difference. But you can always set a tire against a back wall and put it in gear against the tire.
I've done it that way.
Note too that it should be done at operating temperature with the air cleaner on.
Good idea to note weather conditions as well.
That's the thing with Carburetors your setting it for what's going on that day an hour.
But as the weather, engine temperature, humidity etc.. changes it won't be dead on for a tune a month later.
Hence the strip kit for max performance at the track.

 

[lewtot184]

The electric choke has a port that air is pulled thru. Basically it's like a controlled vacuum leak that needs more idle fuel to compensate for this.

 

[Geoff 2]

Put the vac gauge way. Always adjust idle speed AND mixture in gear if auto....because the engine is loaded when in gear with an auto trans.....& the mixture needs to be adjusted for that load.

Adjust mixture screws for highest rpm/smoothest idle; use sight, sound, feel.