I have a 1987 8v old shape Saab 900 2 dr saloon (big bumpers), single Pierburg carb (similar to a Zenith CD), manual choke and electronic ignition (no points).
It starts and idles quite nicely but won't rev past about 3000 revs, there's no misfire or hunting it's simply as if the throttle isn't opening enough. The lever on the outside of the carb goes through its full travel.
I checked the vacuum advance and found that wasn't working, I replaced the unit with a good one and it still doesn't rev out. I know it's ok now as when I suck on the pipe I can see the base plate move and when I do this with the engine running the idle speed increases.
Any ideas?