Turns over, fires, but dies when key released

[SeriesShorty]

Brief history:

Ditched attempts at using electronic distributor, fixed my 25D instead, new wires, new coil, etc.
Confirmed that my TDC is correct and I am not 180 out
Getting lots of good spark finally
All new fuel line, electronic fuel pump, clean filter and clean carburetor (Rochester)
Clean fuel pumping straight from a fresh can
Carb was leaking at base this morning so put new gasket and all is good now
Turns over lovely with my new high ratio starter
Converted from 24v to 12v, new Painless style wiring harness, GM style starter switch, Ford style remote solenoid
She turns over, fires up and goes vroom vroom (boy that is a pretty sound after not hearing it for over a year!)...as long as I hold the key over. As soon as I let the key release it shuts down.

Opinions? Something wired wrong, timing still off?

Thanks all!
Jen

[LaneRover]

My guess would be that that the ignition circuit is wired wrong. That it is currently wired into the starter circuit and only gets power as the starter is getting power, when it should get power when the key is on AND when the starter is getting power.

If it is wired correctly could it be a faulty ignition switch?

Brent

[Gremlin]

don't know anything bout series, but could it be a faulty ignition switch your key is in?

[SeriesShorty]

Thanks for the help Brent. I double checked the ignition circuit and apparently the wiring diagram I used to design my system was incorrect or missing a step. The white wire coming from the GM 2 wire alternator to the ignition switch was the culprit. I hooked it from the switch to the coil to keep the coil hot after the solenoid released the starter. It's not correct but it worked.

She fired right up and just needs to have the carb and timing fine tuned. :D What a beautiful sound indeed. All the neighbors came out to join in on the hooping and hollering.

And thanks to all of the RN forum participants for all the support over the last 2 years getting this truck to this point!