Hi Guys,

This is going to be the stupidest question I've ever posted, but I'm sure it will get the quickest answer...

When adjusting the idle mixture screws on a Weber, does screwing in = leaner, or out? I don't know why I can't wrap my head around this...or find a simple answer online.

The short bus is stopped outside my house.

Turning the screw in shuts off the fuel for that idle circuit. As the cyl goes lean you'll hear it and prob note a stumble.

Thanks!

So....in=lean, out=rich?

Yes. Only gently seated when turning in. DON'T reef on it. Examine the needle tip. A grove can form from excessive pressure. Refer to the CB weber book. It's a great asset for understanding how the webers work and setting them up.

From memory its around 2 and one half turns out,if your idle jets are in the ballpark that is.
I have found in the past if the idle jets are wrong the mixture screws don't respond to adjustment as well or you could have a vacuum leak.

2 1/2 out will get you up and running but it'll be too rich, so dont leave them there too long.

As Rhody guy says, wind them in maybe 1/4 turn each (all at the same time initially from the 2 1/2 starting point and see if it still runs ok (should do)
Then turn in each slowly (individually) until you hear the cylinder "drop out", then back out maybe 1/8 turn from drop out or until that cylinder fires smoothly.
You can get it pretty good using this method, but to be most accurate you'll need a gas analyser to get the CO at between 2.5 & 3%.

Another easy check is go for a ride and see what color the tail pipe is. Black= Too Rich. White= Too lean. Mid Gray is good

Thanks Guys. I got it running pretty well. Carbs balanced and the new Tangerine Racing linkage is huge. Almost done and ready for the summer.

http://www.redlineweber.com/html/Tech/idf_...nt_controls.htm


http://www.carburetion.com/Weber/Tech/idf_...nt_controls.htm