New mower with Kohler engine kept stalling and the self propelled feature is VERY touchy compared to the other (5) commercial 30's I have had in the past. Called Exmark and they were very helpful. They sent out a new vented gas cap and a new tank is on the way. They are aware of the issue. Exmark knows about the touchy self propelled issue that the mower jumps away from you and pulls to the left. This makes it tough and fatiguing to use. My guys usually fight over new equipment but this brand new machine is sitting in my shop right now. No one wants it on their trailer. They are loading the old 30" and 21" machines. That speaks volumes. I am trying to get a hold of the new SCAG 30' to try it out. User's recommendation: Before you buy a new Exmark 30" Kohler, try it out. Pull the bail and walk with it. Notice the pull to the Left. It will throw your straight lines off.