I have done 100's and this little 4.5 has whooped my butt. the drive shaft from motor to lower unit stays in the motor. I dropped the lower unit and took the water pump housing loose. The impeller only had three blades left out of five. Ok I found the problem but the key that locks the impeller to shaft must have fallen in the lower unit. Now I will have to disassemble the lower unit to get impeller key. Anyone ever done this?