Wow!! Another Great Chevy Truck Forum - New Here - Choke Question

[Zilverado]

Wow, just coming by here after visiting ChevyTalk - this is another great looking forum. Just more knowlegable people to hit up for advice, so here goes.

I’m trying to adjust my choke on my carb. I’m not sure the model. According to my Haynes manual, it appears to be a Rochester Q-jet. It has a choke thermostat on the passenger side, with a single wire coming from the cover (electric choke?). It also has a front vacuum break (front passenger side), but no rear vacuum break as shown in my book. So what kind is it???

Anyway, I did the following to adjust the choke and have a question:

First, I adjusted the butterfly with the thermostat (engine off) to just close. Then I adjusted the choke butterfly (while running) on the vacuum screw to open about 1/8". About 30 seconds to a minute after completing this procedure, the butterfly started to open and reached fully open within a couple of minutes. The engine is still cold. Is this right? What’s going on? Should it not choke until the engine is a little warmer? The way it runs, it certainly seems to need more choke.

Please help. Thanks.