Carb tuning help

[manladypig]

Um, as the title says tuning help, but basically how do I do it? Im new to carbs, but I know you got the 2 or 3 different screws, idle speed I think is one. Anyways bought and installed some new spark plugs yesterday and here what the old ones look like:


(one with flash and one without) So with my little amount of knowledge, I'm pretty sure these are sooted and that means its running rich correct? So basically my question is which one of the control screws do I turn, which way, and how much to make it run a little leaner?

[kilrwail]

In the picture taken with a flash, the plug doesn't look as black as some I've seen. How old are the plugs?
To answer your question, you can't adjust the mixture beyond idle speed without changing the jets. You can adjust the idle mixture with the screw that has a flat top and a slot and a spring under its head. The best way to calibrate before beginning to make adjustments is to install new plugs, then tighten that screw all the way in and then loosen it two full turns. Now start the engine and see how it runs. Set the idle speed around 900-1000 RPM. See how it transitions from idle to higher RPM's by giving it a small shot of fuel. If it stumbles on the transition, tighten the mixture screw a quarter turn and try again. Keep fiddling with the idle adjustment screw until it transitions smoothly from idle to at least 3000 RPM. It should remain at least 1-1/2 turns out from the bottom.

[JohnMc]

How is it running because the plugs don't look bad. They are fun to adjust, but try to do one thing at a time so that if you did something wrong you can back track.
Before adjusting the carb I ensure that the car is set up properly - that is timed correctly and the valves are properly adjusted. Also, of course, need to have running to proper heat.
Kilrwail's explanation sounds good.
I usually just follow http://www.redlineweber.com/html/Tech/c ... _best_.htm

[JohnMc]

You can do search for Weber tuning guide and come up with it.