Need some help with my Weber

[tdskip]

Hi guys - on my '74 Spider I'm still having trouble with my hot idle.

She starts with choke cold and will idle around 1,000 RPM. Once warm and with choke off the idle won't come below 2,250 RPM.

The choke and throttle cables appear to be working properly and aren't binding.

Any ideas? If these were SU carb's I'd already have fixed but I am a Weber newbie.

Thanks!

[bradartigue]

Which Weber?

Well, regardless, high idle is usually an air leak. You can tell by screwing the idle stop screw (which adjusts the throttle plate position) all the way out. If the car still idles...you have an air leak.

If you take some carb cleaner you can spray it in light bursts around the carb. If the idle changes where you've sprayed you've found your leak.

Prior to 1979 and starting as early as ... 1970 (maybe before) I think ... FIAT used a high idle device to hold the car at an elevated RPM during downshifts. This prevents excessive detonation. Many no longer work because either the solenoid is bad or the switches in the transmission are no longer connected or working. Easy enough to test, just disconnect the thing from the carb and block off the orifice.

Really a Weber on a FIAT doesn't need any of the "stuff" plugged into it for testing. The charcoal can, ignition distributor advance, other vacuum stuff..you can block these off one by one and find the source of the issue. It can also be in the phelonic (plastic-like) spacer in between the intake manifold and the caburetor, which often break due to being overtightened or just plain old.