'69 skylark dieseling

so ive noticed that sometimes my skylark starts dieseling, but it just started doing it a lot more today...im guessing its carbon build up, im running too rich, or im not using the right fuel...is there anything else that might cause the dieseling? also in the morning when its running at high idle it takes a long time for it to kick down...could this have something to do with the dieseling?

It sounds like a combination of several things! If this is the orginal Rodchester carb you are probabely in need of a rebulid. It first sounds like that your choke is set to rich ( meaning leaving it on too long) next your dash pot which will assist on shut down may be set to shallow
Also if this is 350 which I assume it is some time the exaust crossover in the intake which heats the carb may be plugged or becoming plugged.
I hope some of these suggestions will help.

Gcutllass

so ive noticed that sometimes my skylark starts dieseling, but it just started doing it a lot more today...im guessing its carbon build up, im running too rich, or im not using the right fuel...is there anything else that might cause the dieseling? also in the morning when its running at high idle it takes a long time for it to kick down...could this have something to do with the dieseling?
Advanced timing, too high an idle, as mentioned carbon build up. Does your engine have an anti -diesel solenoid on the carb, this can also be the problem.