180shabah
Rear Admiral
- Joined
- Mar 26, 2005
- Messages
- 4,995
OK, here we go, I have a '96 4.3LX with a Weber 4bbl. The carb has just been pulled and and redone(It needed it very badly). Here is my problem, there are two idle mixture screws(left and right) the screw on the left has absolutely no effect unless it is completely removed, thus allowing unmetered air to be drawn in. The screw on the right behaves as expected, too far in either direction degrades idle stability. I have removed the screw and primary metering assy, and used compressed air to blow through the screw hole followed by carb cleaner. It is not blocked, but still has no effect on idle.<br /><br />A couple more things, The engine has become difficult to start when cold(this is new - it started as usual the first several times after the carb rebuild). Also, the 2,4,6(same side as the bad mixture screw) plugs are a little blacker than they should be.<br /><br />Vacuum is steady at 18(don't trust guage accuracy, but it is stable). engine starts and runs well once it has been run for as little as 30sec, but getting it to start and run 30sec is a PITA.<br /><br />WOT is 4800-4850 which is a little over 200 RPM better than last year, so the carb rebuild did some good. Also, plugs, cap, and coil all new at end of last season. Fuel pump operation and flow has also been verified.<br /><br />I am out of ideas
