Congrats on the 1st run.
Are you sure it's gas on the carb? These carbs will collect quite a bit of condensation when running cold.
Do a finger smell test to see.
If it is gas it could be the float setting, loose fuel line or the dreaded warped casting.
Sometimes fuel will leak down to the fuel pump when sitting. There are valves in the pump that are supposed to stop it but some will leak anyways.
I wouldn't worry too much at this point. Get the engine running smooth 1st. Check/double check points and plugs settings, all wires are good and tight, get the idle to 450-500 rpm and if you have a vacuum gauge adjust the fuel/air setting on the carb to the highest vacuum setting (16 - 21) and set the timing BB directly on the arrow at 450-500 rpm.
That should atleast smooth it out at kidel and low speeds.
If it won't smooth out then I'd go on to troubleshooting the carb.
At this point you could have several adjustments effecting it.
Good luck
Dave
