I'd try backing it off a half turn at a time, drive it, see what happens. When the results turn negative, I'd see if I could improve it again using the other screw. See if I could get it to level out at what it used to be. But I can almost guarantee that thing wasn't bottomed out from the factory. So I'm hoping that loosening that lower screw will give a desired result. But a word of caution. When playing with this kind of thing, it's extremely important to be able to put it back, just like it was. So I'd carefully count the the turns to the bottom on both, then put it back. Then write it down. In my younger days, I've rendered a working machine, to non working, by not being prepared. Sometimes getting it running again can be a real pia. It doesn't have to be exact, but very close.
But really, it seems like it almost has to be an adjustment. Although like I said, I know nothing about a governor.