Re: Stringer 800 tilt quadrant missing teeth.
Is this a saltwater rig? If so, it looks like corrosion/electrolysis started it and mechanical wear finished off. That's my only guess. Slap on a new one and keep an eye on it.
A hint on removing the quadrant bolts, ESPECIALLY if this was a salt water rig. The bolts do not have the easiest access. I think an offset box wrench is the best choice. Try to loosen them but DO NOT force them. If you get any movement but then resistance, apply penetrating oil and tighten them back down. Keep rocking them back and forth, applying penetrating oil each time (and I do not mean WD40) If after several cycles you do not seem to make progress, use a propane torch to heat the area just short of burning/blistering the paint. Then repeat the steps above.
Once out, clean the bolt threads on a wire wheel and chase the holes with a tap. Use brakekleen to blow them out, then apply judicious quantities of Marine grease (full length) on re-installation. The very last thing you want to do is snap one of those bolts.
Even if they seem to come out with minimal effort, back them out a bit, then run them back in to clear the threads. Aluminum is relatively soft and all that detritus, jammed in the bolt threads can distort the threaded holes.