I have nearly the same exact engine on my Locke. Model 200451-0176.
So far, I've found two manuals. You may've seen them previously from Briggs' website:
Generic User and Engine Parts Manual
Have you come across anything in the year since you started this thread? My Locke isn't starting and I've gone through it, nearly a full tear down. Replaced magneto (now have spark, and it hurts), new spark plug, cleaned out the "fish bowl", removed head and cleaned valves, cylinder head and piston and am now cleaning out the carb needles. Hoping that's all it is. These engines are simplistic enough that there really isn't much to go wrong... can't wait to finally have this BEAST slicing away at my lawn!
Funny ha-ha, in the generic user manual, for using the rope starter, the following cautionary note is written:
"When using rope starter to crank engine, use caution so knotted end of rope does not strike persons standing nearby."
I wonder how that came to be? Was Briggs forced to place that there because of a frivolous lawsuit? Either way, made me chuckle.