smoking after overfuel @ startup

[jt20]

can fuel collect in the exhaust system and cause smoking after startup with partial throttle and numerous attemtps?

whats the longest this should last?

All the exhaust from this engine goes through the 85 california catalyst.
Engine does not normally smoke.

Black soot is collecting on the ground, smoke is gray-ish and the car ran very rough once it was started.

normal maintenance has been accomplished.