'79 SA with stock Nikki 4 barrel

We pulled only the top part off to clean the jets, and while we were at it, we replaced the accelerator pump. Of course this solved the problem. Pumped it three times, and fired up after three or four cranks.

Where it gets really frustrating is when it idles at 2800 rpm. We disconnected all three cables, and checked the throttle; it's not stuck open, so we tried closing both fuel valves on the bottom of the carb, which should kill it, correct? It kept going. I'm sure it's just a simple leak somewhere, but we have no idea where to even start. Any ideas?

 

Sounds like a vacuum leak somewhere. Start there, likey suspect is the top gasket on the carb.

 

You can find a lot of information on these carbs, along with troubleshooting and tuning instructions at Sterling's site:

www.sterlingmetalworks.com

There is also a small forum where you can post carb related questions called the BYMC (back yard mechanics club). Unless you are already a carb expert, you should spend some time reading at that site. Lots of good info...




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If all you did was pop the top, you may not have reconnected your altitude idle comp vale, leaving a giant idle vacuum leak. (which would be a great, easy fix!)
Since you messed with the tuning valves, you've exponentially increased your "tail-chasing", though.
I hope you find an obvious problem so that you'll know you've licked the vacuum leak before you try to re-tune the idle.