That sounds like it is getting too much fuel. It could be related to fuel pressure, a leaking injector, and other things. Since you mentioned the half choke concept, it would be a good idea to check fuel pressure. It may be too high due to a faulty regulator or the regulator itself could be drawing fuel through the vacuum causing it to run too rich.
Here is a link that shows in general how to check both the pump pressure and the regulator:
Here are the specs for the pump:
1. Ignition "OFF" for 10 Seconds.
2. With ignition "ON," engine "OFF" and fuel pump running, pressure should be 240-280 kPa (34-41 psi).
Let me know if this helps or what you find.
Sunday, December 23rd, 2018 AT 6:07 PM