The Stovebolt Site Forums The Shop Area Engine Shop 283 4 barrel running rough

I just had my Rochester 4gc carb rebuilt the guy did a fabulous job. The chock wasn't working right now it does but is still starts poorly.

This is an email I sent to my friend who knows a bit more then me.

The car still doesn't really start right... the choke closes right away when you hit the throttle once etc. I gave it one shot of gas yesterday but it still burns rich lots of black crap from the tailpipe and the water vapor is black. It takes awhile to get running smoothly and stalls allot. When I do get it partially warmed up with the choke wide open now and I feather the throttle from the car by hand I can hear it sorta popping as it accelerates then it seems to want to stall if I continue to push the throttle, it sometimes back fires. If I let the throttle go it keeps running. After it warms up it seems to run ok the only thing I adjusted is the mixture screws I set them about 1 1/2 turns out as it says in the book.

With out a license plate on it its hard to get it checked out I'm just searching here. But it sounds to me like a timing issue . Before when I had it on the road to get it tested I would boot it a bit and sometimes it would backfire or miss completely this is before I had the carb done. I know its hard to diagnose over email but what are your thoughts

Of course nothing is easy Yesterday afternoon I bought the car back into the garage I started it with half throttle and it started like a charm it was running at say 1000 rpms and not missing a beat this was after sitting for 3 hours it gradually returned to 450 rpms after brief warm up period.

Any ideas here....Thanks Peter

Here is my take on your problem from my chair.I would check the choke pull off for either being not adjusted properly or lazy.With the motor running it should pull the choke valve open a bit so the motor doesn't load up.Pull it against vacuum to see if it has power or just goes with you.The popping can be,valves too tight,plug wires out of order(check fireing order)or a worn camshaft.Hope this helps.

When i hit the throttle the butterfly closes then when I start the car the valve opens about a 1/4 in or more... Peter