I've converted a Briggs to manual throttle before but it was running on LPG , I think I have seen a few manual throttle petrol ones but can't remember how good the throttle control was running unleaded.
There was no need to remove the air vane when I tried the manual throttle.
The governor system is like a cruise control system. It maintains the speed of your lawn mower or outdoor power products. When Briggs & Stratton governors are adjusted properly, they keep your speed steady regardless of engine load - the amount of work the engine must perform.
