Running too rich-can’t figure it out

1. check to make sure choke is opening all the way
2. check float level
3. check timing - both initial and total
4. Is the cat plugged ?
5. What brand and heat range of spark plug?
6. Coil output ok?
7. ECU working ok? Grounded?
8. Is the heat riser flap frozen shut in the exhaust manifold?