Been away for a week, sorry for the delay in response .
Most mower engines start with the choke closed & the throttle wide open.
The governor i=should be thought as a BRAKE to slow the engine down
The faster the engine is going the stronger the governor tries to slow it down.
Now the throttle control that you move sets the maximum speed that the governor will allow the engine to run at.
The governor is just a bob weight that flings out when the engine is running and turns the governor shaft to CLOSE the throttle.When the engine is not spinning there is no forces pushing the bob weights out so the governor ALLOWS the throttle butterfly to go to the fully open position.
You just have to get it into your gan that the governor is an engine brake to prevent the engine over reving.
When the engine is under high load, it slows down, the governor relaxes so the spring that connects the governor to the throttle control pulls the governor arm towards the fully open position .
The engine gets more fuel, just the same as you flooring the accelerator pedal on your car going up a steep hill.
The throttle opens up wide to provide more power but the engine speed stays the same till the engine is producing more power than needed to maintain he road speed.
At this time the cars governor ( your foot ) backs off the throttle to maintain the fixed road speed lest you get a reminder from the local law you are going too fast .