Great info - I'm in process of doing a detailed condition inspection / MLU on my -8A, and I am having trouble adjusting the mixture control. I can adjust it so, 1) the idle cutoff stop contacts; 2) the full rich stop contacts, or 3) neither stop contacts (about a 1/16th inch air gap on either side.) I cannot seem to get the full range stop to stop, although I was able to make the proper adjustments on the throttle cable. I noticed that the bolt connecting the rod end of the cable to the mixture arm was nowhere close to being "perpendicular" or inline with the holes in the mixture arm and the rod end - it's kinda "flopping around." The bolt is significantly smaller in diameter than the hole in the mixture arm. I thought that maybe the wrong arm or wrong rod end was installed by the OB, but now it seems (after reading this thread) that the mixture arm is missing the bushing.....
Anyway, is this possibly the reason why I cannot get the adjustment to work properly? Is there a proper technique to rigging the cables that I'm missing? On a related note: should there be castle nuts/cotter pins on the bolts connecting the rod ends to the mixture / throttle arms?