SunKing, that's your electric choke. It should normally be connected, but that should be causing hard cold starts, not your problems.
If you have a timing light you can rule out ignition very quickly. No flash, no ignition.
Give your coil a good inspection. Is the case swolen or cracked? Trace ALL the wires from the coil, not just the big one. Are the connections tight and insulation in good shape?
Look at your distributor cap. Is it cracked or loose fitting? Check the points and condenser. Are the wires tight?