I am not tying to leave this thread hanging. I cleaned the barn this weekend and looked everywhere for where I might have put the broken spring. I cannot seem to find it. I did crawl under there and it looks pretty easy to adjust the switch. The evidence makes it seem likely that the spring that was in there was aftermarket. And that makes sense because the plate it pushed against doesn't seem like it is supported very well and sort of "tips" due to the pressure of the spring.
I will adjust the switch and let you know how it works.
