Tilt Lock Repair

[WillemWallace]

I am proud owner of "new to me" 1985 Johnson Sailmaster, model J6SLCOB. I need an opinion on a repair procedure I want to attempt. The motors tilt lock(part #94 in schematic)has sheared off its retaining bolt on the motors stern bracket(part #15 in schematic), probably from trailering in the up position. I want it functional, in order to raise motor from water when I am rowing boat. It is impossible to access the sheared bolt, without disassembling the stern bracket, and then trying to "easy out" the broken bolt. My thought is to simply drill the bolt out from the outside edge of the stern bracket, creating a hole completely through the bracket, the size of the original bolt. My question is: Will this hole weaken the bracket? It seems to me, that the original threaded hole probably went almost all the way through, anyway. Any opinions appreciated! Also, could someone tell me the function of part #66 in the schematic, "tilt knob".
Thank you