Nice work. I work at Briggs & Stratton (27 years now) and this past week I was on a team that disassembled and changed the gear on thousands of these starters.
With all the upgrades you should be set for awhile! I have an old Murray from the mid 90's that I keep in shape. I like the older units as they don't have as much plastic parts.
RU-vid isn't the right placer for support, but no continuity unless your solenoid is engaged. It you measure from the starter's motor terminal to the starter casing or the engine block you should get just a few ohms of resistance. Either Zero or no reading would mean a failure in the armature. @@JaytonMafnas
