Small Engines (Lawn Mowers, etc.): 10 hp lawn tractor, lawn tractor, hi john

Question
Hi john:
My lawn tractor is experiencing some problems. It is almost 20 years old and runs fine. However last time I mowed it started doing this thing where after it starts the power goes up and down almost like it is breathing. I can literally the clutch move everytime it goes down. It doesn't stall and when I engage the mower it evens out but in jsut running mode it is a rough ride as it powers up and down. I was thinking it might have a stuck or rusted float in the carburetor but I'm not even sure it has a float. The engine starts fine and easy and has a clean air filter. Any help would be great.
Thank you

Answer
 Hello Don:

 Look on the Bottom of the Carb and See if there is a Screw with a Spring Around it. If Yes, then Turn it Clock wise Slowly until the Engine Either Stalls or Runs Smoothly. If it Stalls Return the Screw to the Original Setting and Go Counter Clockwise until the Engine Smooths Out or Stalls. If this Process Didnt Help, then the Carb needs to be Cleaned and Overhauled. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John