Small Engines (Lawn Mowers, etc.): Lawnmower idling very high!, clean as a whistle, lawnboy

Question
My 1991 LawnBoy (with 4.5 HP LawnBoy engine) push mower died mid-mow, and instead of first checking the spark plug, I tore into the carburetor, which looked clean as a whistle. After I came to my senses and replaced the spark plug, the engine fired up but it ran very fast,loud and hot, smoked for a minute,and the throttle had no effect. Ran for about 20 minutes,then the rpm's gradually slowed, and it died. Now it tries to turn over but won't start. Did I knock something out of whack when I re-attached the carb? The throttle control attaches down in that area of the air filter/carb assembly, which all has to be removed to get the carburetor open. Thanks for any help!

Answer
Hi Dave,

Yes, you may have changed something when you worked on the carb.  Check the governor/speed airflow flap (if equipped) that is near the carb and adjust its setting.
Next, try squirting fuel into the carb to start it, which would confirm a lack of fuel flow caused by dirt or gum in the carb.  Check for spark when it quits to rule out a coil problem.

Let me know how you make out,
Michael