weber tuning problem

billyroy · 12-02-2007, 01:08 PM

Hi, I have the 258 with a 79 cj and it runs semi rough. I put on a fuel regulator

and then i turn in the idle mixture screw all the way in (lightly) and it doesn't affect the way it runs. Any thoughts on that please? Thank you, Bill

RobP · 12-02-2007, 01:43 PM

No regulator (one ordered from 4wd.com) runs rough.

Keep me posted.....I do have the Weber directions if you'd like me to fax them to you. I haven't gotten that far yet.

Mr.Crowley · 12-02-2007, 06:15 PM

how many turns in on the idle speed screw are ya?If i remember corectly if you have the idle turned in to much you drawl off the secondary circut and the idle mix screw will have no function..I forget who on here told me last year but maybe they will pop in..It is true..

JoonHoss · 12-03-2007, 09:08 AM

Start here:
http://69.0.202.131/html/Tech/Table_of_contents.htm

also, what did you set your FPR at?

Hoss

billyroy · 12-03-2007, 05:43 PM

Thanks for the input, I set the regulator at 3 which is recommended and I have the carb tuning for it already thank you. I will try to get what Mr Crowley suggested and see if that works.I will then repost if that helps. Thank alot, Bill

twmattox · 12-03-2007, 07:58 PM

The two screws that control mixture for low end on the Weber is the idle mixture screw and the speed screw. If your idle mixture screw is too far in, many people compensate by turning the speed screw in (opening up the secondary circuit and allowing the carb to run too rich). Follow your instructions to the letter (it will indicate how many turns in for the speed screw {usually no more than 1.5} and turns out for the mixture screw {usually no more than 2}). Then tune to the lean best setting...