Before you "rewire" the mag plate, which is hard to do because all the wires lead to the sensors and charge coil, you should check for spark at the throttle position you describe. If it starts, then you have spark at that throttle position. Are you sure it is not leaning out and stalling for lack of fuel? Hook a spark checker that can test both coils and not just lay the spark plugs on the block because that motor will throw a 1/2" spark with ease. Once you have the spark tester in position, then move the throttle around and see if you get spark when you pull the starter rope. I would do this with the spark plugs out of the motor for ease of pulling. If you cannot find the spot where the spark dies out, then that is not the problem. Just saying, do the easy stuff first then go and do the difficult stuff.