Is this the linkage I should disconnect?
Both of those vertical rods in your pic are connected to the governor linkage and the rod going to the top of the pic
is a governor control with a knob on top (basically a static speed control).
This means your engine most likely still has its mechanical governor installed. I'd keep it as is and use the common
Mini Bike/Go Kart throttle control that is operated from underneath the fuel tank. This lets you keep the governor intact
and connect a throttle cable. I would remove the knob on the rod so that the rod moves freely or remove it altogether
(rod and all) and set it aside {EDIT: just the rod with the twist knob on it}
See this thread for more info:
https://oldminibikes.com/forum/inde...stall-help-needed-5hp-leaf-blower-b-s.167109/
You will need item #692316 Briggs and Stratton Throttle Control.