Carb issues

[seesix]

My engine sputters, knocks and continues to run briefly after I turn off the ignition. This last 5 – 10 seconds. I notice it more so when the engine is warm. If I shut it off after a short trip it will shut off cleanly.

351 Cleveland 2v autolite 2100. I rebuilt the carb 3 weeks ago.

Is this a timing issue an idle mixture issue or something else.

Some of the vacuum lines (carb & manifold) were removed for the carb rebuild. I forgot to take a picture or diagram the connections so some of the hoses may not be exactly correct. I have spent some time capping and changing them for the desired result with no success. I think it may be more than just a vacuum thing though.

I need some help, this can’t be good on my engine.

 

[10secgoal]

If it's a stick, hit the brakes and slip the clutch like you are trying to kill the car. That will at least stop it from dieseling.
There could many things. Could be lean, hot spots, cheap gas for high compression,timing to far advanced or motor is running too hot.

 

[Decurion]

I would start by checking the timing. If its too far RETARDED, it will run-on. Since you have a 2 barrell, Ill assume the rest of the engine is basically stock. I would start by setting the timing to about 10* btdc. Then start looking for vacuum leaks. If you dont find any, try setting the mixture screws. If you havent done it before, a vacuum gauge will help, but basically just turn each mixture screw in or out SLOWLY until the highest rpm/vacuum is achieved. In the end each mixture screw should be about the same number of turns out. Then set the idle speed to where it should be, probably around 800 rpm. All this should be done on a hot engine. That should get you close. My guess is the carb is just not tuned right.