Tim, dang! I hope your recovery is 100% too. Having something like that happen has to reset your priorities.

I can't recall my CDI box (several of them over the years) ever getting hot enough to even notice it was hot. Since you have the classic Retrofit CDI box, you should first contact the vendor (I forget his name, but he participates on this Forum) and tell him about the hot box. He's very responsive.

5 months back, I also suggested that you swap the coil and see if that makes a difference. If you have not one that yet, do so. It only takes a few minutes.

I think your problem remains ignition related, not CIS related.

OK - firstly thanks for the feedback regarding my health. Great knowing I have people wishing me well from around the world, not just local friends.

Bit more feedback - I replaced the CDI box today with a factory original (borrowed from a local friend) and the problem did not go away - still just works fine for about 5 mins then as the engine settles into what would normally be full running mode (not warm up mode) it misbehaves.

I have previously changed the coil (I have 3 working coils I can swap)
I have checked the fuel pump circuitry and its all OK - and would not make sense to be cutting in and out once warmed up.

Next item I plan to check is the Supplementary Air Valve - its in parallel with the Warm Up Regulator, so worth a check - I am wondering if just electrically isolating it/disconnecting it will highlight if that is the cause of the problem once everything is warmed up. Otherwise I'll look to borrow one and see if that fixes the issue.

Tim,

The Aux air valve is "more" open when the car is cold, as such it provides more air to the meter plate and raises it. This provides more fuel along with air. So in cold weather it increases the "idle" for a while (warm up mode) As the wires to the element in the Aux air valve heat it up, the valve closes to provide much less "extra" air, and the idle gets to its normal value. So if at start-up with a cold engine, if your idle rises to say 2K rpm, and then slows as the engine "warms", your Aux air valve is likely working fine. It is easy to disconnect electrically, and then it should stay as open longer (maybe engine heat will start to shut the valve, I'm not sure). My gut tells me the Aux air valve is not your issue, but testing with the wire disconnected is pretty easy to do.

I had a similar cut out issue with my SC and it was a bad fuel injector. I see you have metal lines so pulling them for inspection is a chore I've never done. Mine are flexible lines and easy to pull. Can't really advise if there is a way to test your injectors with metal lines in the car or not, sorry. If you can, you can get vials for each injector (at Amazon) and inspect them for drips, spray pattern and equal volume. Be sure to have a fire extinguisher handy if you do this test (as a precaution).