Check Engine light for GC25K. Any Advise?

-The Mixer has been replaced with new Unit. (New Gaskets/diaphragm)
-New Spark Plugs
-New Universal 02 Sensor
-New Timing belt (timing is spot on)/ was off by one gear before new belt was installed.
-New Diaphragm on top of Carburetor/Throttle body.
-Pedal Sensor is verified Good and in range.
-Engine Temp sensor appears to be working fine as Temp gauge appears to warm up and cool as thermostat opens to allow cooling fluid to cool engine.
-flywheel sensor appears to be working since technician could read RPMs when computer was attached.
-All vacuum lines appear to be in excellent condition with no leaks or cracks.

Technician with computer attached could not seem to get the dwell to adjust properly via the throttle body adjustment screw. Dwell drops to zero when idling for a long time causing the check engine light to illuminate and motor to go into limp mode. If you full throttle the engine, the dwell pegs out at 100 and after 1 minute 30 seconds, the check engine light comes on and engine goes into limp mode.

The computer does not give a flashing code. it appears to be the older computer that has a vacuum line attached.

To summarize the issue, Check engine light comes on if unit idles for to long or is revved for to long. When the light comes on Engine goes into limp mode. You can turn the key off and back on again quickly, and this seems to delete the check engine light until it comes back on again due to the idle or high revved motor condition.

What are we missing/overlooking?