Briggs and stratton throttle/governor assembly

First, loosen the arm until it is moving freely. Next, open the throttle to full capacity while making a note of which direction the arm moves in when the throttle moves through it. Once the throttle is fully opened, move the governor shaft in the same direction the governor arm traveled.
https://www.hunker.com/12359232/how-to-adjust-a-briggs-stratton-governor

you adjusted your governor incorrectly.

First make sure the throttle lever is on full speed position then unloosen the bolt that holds the governor lever to the shaft which protrudes from the engine then with plyers turn the shaft the same direction that the spring pulls the governor lever until it stops then tighten the bolt the holds the governor lever to the shaft. Sometimes the governor shaft might have a screwdriver slot in it to turn it.

Should see a bracket with holes in it .and a small throttle bracket that has a hook shape the spring locks on to it.

Sometimes the governor gear inside the engine breaks and you have to replace it. Did you try to adjust the governor by putting the throttle full and unloosen the screw on the governor arm and push the governor piece the same direction as the throttle opens and tighten the screw.

Just guessing here, but if there is no control of the throttle and the engine over revs, then more than likely the governor control is broke. Briggs if famous for that problem. Governor is around 25 dollars and a lower crankcase gasket. Requires the engine to be pulled, lower crankcase removed, remove all pieces of old governor and then re assemble with new governor and gasket.////Before doing all this check that both springs are on the governor on the exterior of motor. If you manually hold the governor arm back, counterclockwise, and it still revs, then you need to replace governor. Don't let it rev for long or it with throw a pushrod or worse. good luck

It could be that the governor spring has become disconnected or has broken on an end where it hooks onto the throttle linkage. If the spring is OK & throttle linkage is not binding it could mean the governor drive inside the engine has failed preventing the governor from operating correctly. You may need to take the engine to a mechanic to fix the problem.

see http://forum.doityourself.com/outdoor-power-equipment-small-engines/384248-spring-locations

Go to this site or type into search

briggs &strattone ngine

bsppwebtools.com/data/manuals/1678_0esfw.pdf

The engine speed is controlled by a governor and throttle position. There is a spring that holds the throttle (butterfly valve) against the slower position. When the motor is under load' the governor exerts force to open the throttle position. Make sure that all of the components are clean and not binding. Look for a broken or disconnected spring. It is also possible that the governor is stuck in the demand full throttle position.