I recently completed a major tune-up on my 15hp Evinrude. This included a water pump replacement. Of course, I am having difficulty reconnecting the lower unit. On this last attempt, I successfully got the linkage connected, but then could not get the motor to shift. It was stuck in forward. In fact, past forward. I disconnected it again, and it seems like the lower shift rod will not change gears. How do I successfully change gears with the lower shift rod? Thank you for all your help.