If engine has preformance issues, this will effect hydrostat preformance, make sure engine is in good working order

First: You change hidraulic oil in 3000hrs?
Second:Note if engine up idler speed before wheels rotating(otherwise you have a syncronization problem of pedals).
In this case in platefoot has a black box of pedals,in center has a screw allen 4mm with lockrod ,this regulatin a begin of aceleration of engine.You have a 180º of ajust (do not traspassing this limit) unscrew rod and moving allen screw clockwise or counterclockwise easy and check pressing pedal and hear the engine uper idle speed before the wheels rotating,ok. Sorry my inglish is poor...