air / fuel mixture screw

I don't have a Colortune yet, but want to get close in my setting of the air / fuel mixture. When the screw is all the way in, is that richest or leanest?

Any advice as to how to set air/fuel mixture screw from scrath greatly appreciated. I am setting all at three turns out, and going from there.

Carbs are synched and engine idles OK. When it is cold, tapping the throttle reacts beautifully, but when hot, it is mushing out.

Thanks very much,
Jt

 

In for lean, out for rich. Take a look at your plugs and work INCREMENTALLY from there.

I don't suppose you made a note of the settings before you disturbed the screws, did you?

 

Actually, I did record how far I needed to screw them in all the way before backing them off three turns. The data ranges between 1.5 and 5 turns. The center screws are chewed up from previous owner, are they easily replaceable?

Do I need to clean the plugs each iteration, or would a lean condition burn off the soot. Currently they are intensely sooty.

 

You might want to get a couple sets of plugs. If they were at a strange range of settings, you could TRY them there and see what you get. If three of them were between 1.5 and 2.5 ond only one at 5, then it was probably NOT really supposed to be there.

I would start at 2.5 turns though if you're that rich.