In case you don't know, the system comes with a key. I had been using the metal, hex-style end to put into one of the holes on the top of each head; I twist it one way or the other and that is supposed to shorten the left-most side of the arc. Alas, the arc didn't change. After carefully reading the instructions, I realized that I needed to use the other end, the plastic end that's wider and have notches on the end.
I did that ... and it's gotten worse. Not only do the heads (and I only tried to fix two of them; there are several others I still need to get to) still water pavement, they arc even further, jutting out onto the street and well into my neighbor's driveway. I'm scared as hell one of the sprinklers will hit my neighbor as they're walking to the car, or they'll see their car drenched in water and that'll piss them off. Worse off, the right-most side of the arc is different, too. You can't use that key to fix the right side. Instead, you have to literally take out the sprinkler head and re-orient it so that its right-most extent lines up with the edge of the grass you want to water. I was able to twist off one of them, and I thought I had put it in correctly, but now that's watering my walkway. I think it's hitting the side of the house, too.
Add that those sprinkler heads are a bitch to take out of the ground -- you have to dig around the head, and sometimes twisting and pulling them is difficult, and by the way, I was unable to find the ones I tried to fix without turning on the cycle so that the heads pop out from the dirt and grass that seemingly was buried above them, and that's a pain in the ass -- and after a bit more failed tinkering (I did all of this on Wednesday because I came home from work early), I quit. Maybe I'll try again Sunday. But even though the grass is yellow and crusty, I dare not turn on the sprinklers now, now that I've made a slightly bad situation a lot worse. I just need to fix these damn things.