Hi, I replaced the water pump on my dad's 40hp outboard and successfully put it back together. however I only found three of the impellers and after consulting this forum i took the bottom end off again and retrieved the other three. when I put the motor back together it was stuck in forward and the shifter was frozen. so i took it back apart and tried to shift geaar with the bottom end removed. It was still frozen. then i shifted the bottom end into neutral and reassembled the motor to see if that would help. the shifter is still frozen and the motor moved into forward gear when I was putting it back together. what am i doing wrong?