Small Engines (Lawn Mowers, etc.): Mower Hit Curb, air fuel ratio, crossover pipe

Question
Hello, My Sears mower with a Briggs 122T00 (6.25 engine) hit the curb recently.  The blade grabbed the skirt in the back and was wedged.  I was able to free and restart.  Engine was running slower and slightly rough.  Blade bent, so I replaced along with new skirt.  I pulled flywheel and replaced key, but it was OK any way.  I adjusted speed by bending spring bracket.  It starts easily, has good power, but the RPM is not steady.  It is not horribly rough either.  Do you think something happened to the internal governot mechanism?  I am guessing the crank is not bent.  I rotate both ends of the new blade past the same spot on the mower housing and it looks the same.  Just wondering what else could have caused the engine to be running slighly rough?

Answer
Is your gasoline fresh from the pump?  Make sure that the crossover pipe that the carb bolts onto did not crack.  This will cause the air fuel ratio to get messed up causing the hunting symptoms you describe.

I doubt the internal gov gear got messed up.