Can't help much without Briggs Model-Type-Code number.
XXXXXX-XXXX-XX XXXXXXXX

Most small engines used on modern lawnmowers use a "wind vane" type governor. Essentially there is a small flap of metal that sits in the wind that is generated by the cooling fan, located on top of the engine. The vane tends to pull the throttle closed, slowing the engine down. There will be an opposing spring, generally located on the carburetor, where you can see it, that is set up to pull the throttle open. So these two parts are connected, and they work in opposition to one another. When the engine is at idle, the cooling fan is making little wind, and the spring dominates, opening the throttle. When the engine comes up to speed, say 3000 rpm, the force of the cooling air activates the metal vane, and it dominates the spring, pulling the throttle closed a bit.

Most likely it's a carb-on-tank style and it looks like this.

thanks for the pic,is it the flapper type that the spring is connected to.the arm that comes down on mine was not connected to a spring so that may be the problem.it all started when I pushed the mower under a bush.do you think that's how the spring came off. ill try and load a pic to my next post.

I've seen many mowers, when pushed under a bush, where the metal tang on the right side of the spring has been bent inward, causing a low engine speed. If so, bend it to a 90 degree angle, looking down, and you'll be close.

from all the info I've found on the net there are 3 places the engine numbers should be.i have gone over this engine with a magnifying glass and I cannot find any anywhere.i bought this mower from kmart and have not taken anything off the engine but I cannot locate this info

Front of the shroud, above the spark plug, stamped into the metal.

nope

Does it have or did it have a tin deflector over the muffler w/ numbers stamped? Stamped in the valve cover if an OHV?Or things would be more visible w/ the plastic dress cover off? May just have to snap a pic.

that's the frustrating part nothing has been removed or changed but I can't find a number