I have a 1982 Mercury 115 outboard motor, every time I try to put it in gear, the motor will rev just like it should but I get no response from the prop (in forward nor in reverse). We have checked all of the cables and no for a fact that they are not the problem. When you put it in gear, you can spend the prop one way without a problem and with no noise; but when you spin in the other direction it will make a clicking sound. We have taken the lower unit apart and can't seem to figure out how to take the entire bottom part apart, but we know for a fact that the problem is in there. When you spend the tall shaft (that goes into the upper unit) the prop shaft does nothing. What is wrong?