ADFA carburetor help

[wubie317]

A couple weeks ago, I replaced one 32 ADFA with another that I had painstakingly rebuilt.

For a week I had all kinds of trouble...sticky throttle linkage, and really inconsistent idle when it was warmed up. If I kept driving without stopping, it was fine. But if I turned off the engine and left it when it was hot, idle would want to drop to zero, sputtering, and ugliness on acceleration. Yesterday, I realized the 4.5mil spacer was a required element of the setup, which I installed and everything seemed pretty good. For a while.

When it's cold, it starts immediately and runs really well. The high-idle is too high (like 3K RPM...how do you adjust that?) but I'll get that sorted. When it warmed, idle dropped to about 1K and all was pretty good...seems a little rough, but not terrible.

Today, I drove it for 30 minutes on the freeway and it was running well until I exited the freeway. As I was slowing, it started sputtering and shuddering at 1K-2.5K quite badly. It wouldn't idle, dropping to zero and nearly dying. I could only get it into a parking spot by keeping on the gas to keep the revs up. 15 mins later, I returned to the car, started it and limped to my destination by feathering the gas pedal.

After sitting for 2 hours and cooling down almost completely, it started right up, kept idle at about 1K and made it back nicely.

What gives? Where do I start looking to solve this problem? I read somewhere that Webers do not like hot gas (I thought the insulator spacer would resolve that problem) and I understand that about 80% of driving is on the idle circuit which should get supplanted at about 2500 RPM (thus, my belief that the problem is in that set of parts). The rebuild isn't exactly the same as the old one (which had its own set of problems), but all the jets are in stock spec according to Brad Artigues posts (I used both the old and the new idle jet sizes, no difference) and the mains are slightly larger on the old carb...155 and 135 on old vs. 160 and 140 on the new.

Any thoughts?

[Nanonevol]

Since it runs ok most of the time it seems the jetting must be ok. The water choke is adjustable - possible some of the problem is there. Assuming the fuel filter is not clogged but is the fuel pump stock? Can you test its operation? Brainstorming here.

[kmoses]

Check the nut on each end of the throttle plate shafts (the ones with locking tabs). I was trying to find the cause of occasional high idle and after adjusting the idle speed screw the idle would then go low. The linkage was binding when things got hot. I bent the tab back and backed off the nuts one flat. This solved my erratic idle problem.