Hi all, We've got a Toro, I believe it's a model Z148, 18 HP Kohler on it. Since we've gotten it we've had an issue with a particular job we have with alot of bumps on it. It seems that if I go over to many bumps and ruts in a row, the engine starts to die and sputter. Once I get back on to relatively smooth ground and slow the ground speed everything is fine, until the next set of ruts. Is this a fixable issue or is it due to the engine being carburated and not EFI?