I understand your frustration - what the heck difference does it make to the local dealer where it was bought? It's out of warranty - they will be able to bill the customer for the work? I don't understand it
Here's what I would do:
First, get in touch with the factory - get online and try to email them. Try to find out who the rep is for your region. They should be concerned about what kind of service their dealers are giving the customer - and they should be concerned about one of their motors catching on fire, even though it is very rare.
Secondly, I would get myself a Yamaha shop manual for my model outboard and check out the wiring diagrams. Look at which fused circuit provides power to the rectifier/regulator (if that's where you think the short occured). Pull the fuse, if it is still there, and try to determine why it did not blow. All of the circuits, except for power to the starter relay, should be fused. And,
really, I wish Yamaha would fuse it also. Maybe, that's where a short occured, if so, then it's like several hundred amps of current feeding a dead short, and either the short burns open quickly, or there is going to be ignition of adjacent materials.
From what I have read on this and other forums, Yamaha's four strokes are very reliable - what you have experienced is very rare, and I don't blame you for wanting to find out the cause. Let us know how you come out.
Good luck [img]smile.gif[/img] ,