Raw Fuel Out Exhaust

Pull the spark plugs and see if any of them are wet.
If they are all wet then look at troubleshooting the carb.
If only one plug is wet then you look into that particular cylinder valve train.

If the plugs are dry and look healthy/normal then the black liquid coming out of the exhaust is probably condensation with a little bit of unburned fuel residue mixed in with the black soot from a rich burn upon initial startup.

I once had a compression ring fail on one cylinder. The plug would fire but the fuel would not burn properly and the plug would be wet with fuel. Of course the compression test indicated which cylinder to address. I replaced the rings and the problem went away.