I have a 2007 40 hp 4 stroke tiller with less then 50 hrs bough new in 2009 as a leftover...from day 1 of use I have had the same problem with the motor. It wants to or does stall when you bring it back fast from full throttle...runs fine otherwise..after several visits under warranty and after the problem has never been fixed..changed fuel, fuel tank, plugs, installed water separator.750 later same problem...Anybody have any suggestions other then the obvious of find a new mechanic??? Thank you.