Mario;

It sure sounds like the electronic ignition may be the cause, although if there is a diode to the Terminal 50 of ignition switch, similar to the other electronic conversions, and this diode is bad, this could explain the symptom of firing during cranking, but not running after that....

...but, you need to figure out what blows F2 for starters!

Also. What rating is F2? Fuse2 is originally an 8A fuse...and all of the loads it supplies (Reversing lights, Horns, Brake lights *) are only "occasional use items". If you added the Ignition load to this fuse, did you increase it's rating (by the amount the ignition system's inline fuse is rated at)?

Which side of the Fuse2 did you power the IGN system from...by wiring the IGN sys to the protected side, you might think your doing a good thing, but a blown F2, due to for instance a shorted horn, will dissable the IGN...not so good....it should be the INPUT from IGN switch, so that blowing f2 doesn't kill the IGN...(it has its own fuse anyway).

Good Hunting

* reference: http://www.intelab.com/swem/122S%20Wiring%20Diagram.jpg