carb issue

If the fuel bowl is draining overnight, than the oil in sump would smell of fuel, and perhaps read high on dip stick. Diluted oil is bad for bearings. Repair carburetor, and change oil ASAP.

One thing that would allow fuel to leak into manifold is an incorrectly assembled accelerator pump.

Another cause of hard cold start would be incorrectly adjusted choke.

After car sits all night, remove air cleaner, manually flip throttle lever to set choke in closed position. If the butter fly valve does not fully close, the engine will not start easily if at all. If the choke snaps closed snugly than it is doing its job, and should crack open about a 1/4th inch once engine fires.