Your setup looks fine as long as the clevis is not wiggling around on the threaded rod. If you can feel movement, put a nut on it. There is no way that those rods are going to unscrew. Even if they could turn, the would unscrew out of one end and into the other. As long as you have the length of threaded rod in the clevis that you have, the threads will bottom on one end or the other before it can part company with the clevis. It just ain't going to happen.

However what is the deal with the throttle linkage, why the big bend in the cable and where is the lock screw on the quick link. I'm guessing from the photo that your quick link is set way to tight on the servo arm and isn't rotating on the arm correctly. That bend in the cable stands a chance of folding over from the looks of it. Make sure the quick link turn freely, but isn't so loose it might pop off. I use them for throttle linkages and I've at times put the Jam nut on way to tight, giving me the condition your photo show. If you take a picket knife and work it under the jam nut carefully, all the way around it, you can get it loose enough to turn easily on the arm.

Don