Tecumseh 5.5hp LEV120

My Craftsman power washer is powered by a Tecumseh 5.5hp LEV120. It would start but not stay running. I removed the high speed bowl nut on the carb and it was clogged. The two holes across the nut were clear but the hole in the nut that goes to the main nozzle tube was clogged. I used a very small drill bit to clean it out. The engine now runs but not well. It acts as though it is too rich. There are no adjustments on this carb. Is the diameter of this hole critical? I probably should just buy a new nut.

Can I add a carb cleaner treatment to the gas to clean some of the other passage ways in the carb?

I put "Sta-Bil" in my gas when storing for the winter. Am I better off draining the gas for the winter? Thanks for your advice.

 

You may have missed the tiny hole at the top, on some it is almost invisible when dirty and will create your problem, refer to the photo for reference only. Have a good one. Geo
http://i190.photobucket.com/albums/z...c_bowl_nut.jpg

 

The diameter of the hole is critical and using a drill bit surely changed it.