Need Help With Weber Carbs, Won't idle Options

[michael7810]

1972 1911cc with IDF40 carbs, 50 idle, 140 mains, 220 AC jets. Engine & carbs were rebuilt 13K miles ago. Plugs and all ignition parts replaced about 3K miles ago. I have not driven the car much since June, in fact I have not put gas in it since April. My car ran great the last time I drove it about 6 weeks ago. It's finally cooling off in Phoenix so I decided to get it ready for winter driving. So before starting it up I replaced the accelerator pump diaphragms and pulled the float covers off. The bowls were dry and I noticed that 1 of the floats was starting to crumble so I installed 2 new floats, set at 10mm and 32.5mm per the Weber manual. The car started up normal but would not idle. It was running rich (9.0 on the AFR gauge). I let it warm up and it still would not idle, it usually idles fine once the heads heat up to 200F. I adjusted the throttle plate stop screw in a turn to increase the idle and it barely idled, still very rich. i turned the mixture screws in all the way and it idled a little faster but still very rough. The AFR did go up to about 12.0. I cleaned all idle jets and it didn't change. Still the best idle I can get is with all mixture screws turned in all the way. I drained the gas and replaced with fresh Shell premium but that did nothing. It revs OK and runs smooth above about 2K RPM. It seems the problem is with the idle circuit. Is there a way to clean out the idle circuit without disassembling the carbs?
Thanks for any help/suggestions.
Mike

[rhodyguy]

Do you own the CB performance weber book? The trouble shooting, symptom, possible cause is invaluable. I would go thru the pre-install procedure.

Is it ONLY running poorly at idle and fine @ 2700 rpm? Try turning the the driver's idle speed adj screw, ONLY, to raise the idle. Now measure the flow on the the front venturis on each carb. They should measure the same. If not, the linkage is out of adjustment. If you're fighting a balky linkage you'll never get anywhere.

[michael7810]

Do you own the CB performance weber book? The trouble shooting, symptom, possible cause is invaluable. I would go thru the pre-install procedure.

Is it ONLY running poorly at idle and fine @ 2700 rpm? Try turning the the driver's idle speed adj screw, ONLY, to raise the idle. Now measure the flow on the the front venturis on each carb. They should measure the same. If not, the linkage is out of adjustment. If you're fighting a balky linkage you'll never get anywhere.

I have the Tangerine cable linkage which is flawless from a sync standpoint. And I have the CB Weber book. I need to make sure the throttle plates are set per the book. For now it's drivable and runs great above idle. It actually doesn't idle bad now just not as good as it ran before the long summer rest.