Trying to remove lower utnit on 1978 15hp evinrude, long shaft, have loosened up top screw for shifter rod above extension have unit in neutrel but can not remove unit to change water pump.I noticed two clamps on shifter rod I do not see how I can loosen bottom clamp let alone reinstall.I have tryed shifting gears did not seem to leave room to get to bottom clamp, and I am beginning to think that is the one that has to come loose,are these screws supposed to come completly out? Thanks for any help. Ken