I have a 2004 Tiger Cub with the Kaw 19 hp engine and it pulsates when going up hills on the right hand side pump??? Also cant get to start with key any longer but think I can figure that one out from past posts here.. has 700 hours and only does my 2.5 acres every week, bought 7 years ago with 120 hours. Admitting I have only changed the hydraulics one time based on smell,if it smelled good I left it.. changed it 2 years ago.. this pulsating was present when I first bought it but I have just learned not to force it and take my time allowing it to settle down.