Got 4 21" 2cycles and all have problems. Need some help. Two are 4 yrs old and two are 7yrs old. problems by mower mower 1 fly wheel is catching on something inside, I can turn it freely using the blade, it will turn for a while but then it catches whatever us stopping it. I can force it past it but if it is running it stops like it was bogged down. Looking in at the piston through the carb I noticed two good size nicks on the piston. This is one of my new mowers, The mulching baffles are still intact, that's how new it is. mower 2 swapped a trans from another unit, but only left well turns, right does nothing. Also at full throttle the RMS are going crazy. I can throttle it down and it will idle but at full throttle it sounds like it is about to take off (in the air I mean). This is one of the older mowers. mower 3 broke a belt few weeks back, in the process of removing the blade and cover I broke the pulley. Mower sat for about a month. Finally got around to fixing it today. swapped a pulley (cannibalized I should say). Once I got it all back together it started fine, was burning some white smoke, figure it was some oil since it was on it's side most of the morning. Ran it awhile, ran o.k. but not great RMS seemed a little low but not bad finally quite smoking. Figured I'd adjust the throttle cable, but before I could it stopped running while I was still mowing. Also started smoking again. I parked it and let it sit. Went back to it about an hour later still would crank. Mower 4 on of the newer ones, sits in pieces been parted out, also doesn't run, can't remember why. I'm about to go crazy. Everything is going wrong. Nothing is working, scag, 4 toro's, 2 walkers. But that is another post, stay tuned.