Okay, there are two things to check. 1st, do you have hydraulic remotes on the rear? If so, make sure the handles are centered. If they stick and don't return to center, your 3PH will not work.
Most likely you have an out-of-place (loose) power beyond plug inside your FEL joystick valve. Look at the photo and illustration below. You need to remove he cowling around your joystick and remove the circled cover. There is a small plug beneath that cover that loosens and allows fluid to bypass the rest of the system and go directly to the reservoir.