I have a 235 six. A friend gave me a remanufactured Rochester B for my truck. The float level was set to specs. The only thing that I replaced on this carb was to add a .055 jet in place of the .051 jet that was in there. I was able to get 19” in vacuum and set the idle at around 650. Everything seemed fine.

It drove real nice around town but I noticed the idle would keep going down at every stop light. A smooth idle but it would get lower and lower. After I got it home I tried to restart it after 10 minutes and it would not start at all. It wasn’t leaking and I didn’t smell gas.

I ended up taking this carb off and putting my old “B” back on. Is it possible that the power piston is sticking or maybe a faulty idle mixture screw? I checked the power piston and it moves freely. All other non carb settings on my truck have been checked. Dwell is around 30 and the timing is set at 10 degrees BTDC.

Thanks for any help.

1956 Chevy 3200, 1/2 Ton, 235 CI
https://photos.app.goo.gl/TQQo1YnFjs3U7xB57