Matt, when you did your start sequence I heard the typical beeps before it should initiate a start followed by a single lower pitched beep that lower pitched beep indicates a low rpm error. I had a pegasus that did that to me and it was the rpm sensor had failed. To be fair the sensor itself hadn't failed but the cable connecting it was pinched and caused a problem. I took the pressure off the cable and it solved the issue in my situation. I wonder when you are connected to the PC if you blew air into the engine to spin it if you would get an rpm reading. Funny it worked once for you but not now. Check the connection on your rpm sensor at least. In all seriousness though if it's not something you decide you want to mess around with let me know. I would be interested in the engine.
For what it's worth, unless you want a more current engine I do believe this engine is more than worth having Bennie look at.