I started working on engine control rigging the other day but didn't have the right hardware. Specifically, OP-22 calls out AN3 bolts drilled for castle nuts for the mixture bell crank assy and a couple of specialty washers as well. I spent several hours yesterday looking for these locally and ultimately got most of what I needed at Airparts then ordered the rest. Unfortunately, the print was a little optimistic on the length. The ones on the ends of the bell crank are called out as AN3-10, but that's way too long for one of them, requiring 3-4 extra washers. -7 would be better, so I'm going to have to get different ones. Started the day by pulling the sniffle valve plug in the sump and draining residual pickling oil out, then installing the sniffle valve. I also did the final install of the fuel servo, including torquing the nuts to 204 inch lbs per Lycoming service instruction 1484C. Rigged the throttle cable and safetied. The gap at the panel when the knob is full fwd are set at approx 1/8". Then rigged the mixture cable and bell crank assy to match I will say that the mixture bell crank is quite finicky and its hard to get it set so that you get full throw both ways with smooth travel, and all the other requirements met. Per print, you use two heim joints screwed into each other to make a really short adjustable pushrod that links the bell crank and mixture arm on the servo. This is shown on the print as having the female joint fwd and the male aft, but in my case, this was causing the assembly to rub on the arm of the servo at the full fwd range of travel. I flipped it around the other way so that the skinny threads coming off the male end were in that area and eliminated the issue. All adjustable components of this are positioned torqued, safetied etc. Once the correct drilled bolts arrive I will replace the undrilled AN3 bolts with the right ones. I might also mention that I had to reclock both servo arms. The Precision air silver hawk manual gives a torque value for both shaft nuts. The throttle one is easy because it's a castle nut that just needs a new cotter pin after torquing, but the one on the mixture side is a fiber lock and in addition to the torque value theres a warning in the manual that anytime you loosen that nut you're required to replace it. Now I'm 100% sure that's just some lawyer CYA stuff because in every application Im familiar with, standard practice is to reuse fiber lock nuts as long as they still have friction drag when you screw them on. However, fuel delivery is kind of a big deal, so I'm going to go by the book and now that I've got everything positioned properly I'll replace it with new. This is a little frustrating. I wish they would have left the arm off or at least send a spare nut in the hardware back because its a virtual certainty that you're gonna have to reclock that thing, and it's a non standard special part. I put one in my shopping cart at spruce, but it's out of stock so who knows when that's gonna happen.