Hi - thanks for responding. I checked the fuse today. It blows as soon as I move the switch to the ON position.
Regarding the parts, the ignition switch was a guess, since I didn't want to work on it... However, I then checked to the best of my ability the continuity of all the wiring, toggling all the switches and making sure that they were working right. At that point, I pulled out the regulator and tested it. I checked for resistance between the two yellow leads and there wasn't any continuity. I thought (maybe incorrectly) that meant that it was bad, so I ordered a new one. However, when I got the new regulator and tested it the same way, there was no continuity either. Therefore, I assumed I tested incorrectly, and decided I needed to check the starter. I planned on applying power and making sure it spun. Somewhat clueless, I unscrewed the bolts that hold the two ends of the casing together. There were three spring-loaded terminals that connected to shaft which came out when I disassembled it. I managed to get them back on, but I was pretty sure I broke it anyway. So I tested the starter after I put it together, and it didn't spin. So I ordered a new starter. So now you know my experience level...
Anyway, I have long suspected a short in the wiring, but I searched the wiring looking were it passes through a hole or anywhere it could be rubbing. Everything looks fine. I don't know how to properly test for a short, but I tried testing for continuity between various points and ground, but I didn't find any continuity.
As for unplugging the hour meter and PTO, are you asking me to unplug them just to see if the fuse blows? I didn't check anything with the hour meter. On the PTO I checked all the terminals to make sure it was switching properly and it seemed fine.
Thank you both for responding.