Small Engines (Lawn Mowers, etc.): Kawasaki 17hp engine surge, gas cans, carburetor

Question
I have a Scag 48" hydro walkbehind with a 17 hp Kawasaki on it the mower is only
two years old and last year it quit running and a dealer rebuilt the carb and
told me it was not under warranty but now it is surging real bad again even
after it runs for about an hour the surge is still there mainly on lower rpm


Answer
Most likely the carb is dirty again as this is the most common reason for surging.

Are you gas cans clean?  A few years ago we had the same problem with a commercial company.  We had to clean the carbs every week due to small, very small debris entering the low speed carb circuit causing there engines to surge.  One day we stepped outside and i noticed the gas cans, near the cut grass container, did not have any caps.  Turned out the cans were full of very small debris and kept finding their way into the carb via refilling the equipment.

I would recommmend cleaning the carb with compressed air and carburetor cleaner and see if the surging stops.
Let me know what happens.
Eric