Alright fellow gearheads I have a 15 horse Kohler command model cv15s. It was not running very smooth so I did a leak down test. The only air escaping was out the dip stick tube. I did a compression check and I had 120 pounds. I did not expect this much compression. The next logical step was installing a carb off a good running engine and it still ran poor. After all, the original carb may have something wrong with it, even after cleaning it. I figured the head needed to come off, and sure enough it was leaking even with 120 lbs of compression. The cylinder wall looked very good, with no scratches except for the crosshatching. That eliminated the possibility of a broken ring. After cleaning the carb again and installing a new head gasket, I started it up and it still ran very poorly!!!!!! SOOOOOOOOOOO, I took another head of off another engine that was known to run good. Still ran bad. I even tried switching the known good coil, still ran poorly I even tried changing the oil figuring maybe the hydraulic valves were sticking or something. STILL RAN BAD!!!!!!!! Its backfiring a little and sputtering while it runs What the heck is the deal?????????????? The only thing left is that maybe the hydraulic lifters are bad?? I am at my wits end on this one Any suggestions?