Alright a buddy of mind just got ahold of me and said he has a 1970s- 80s 40hp mercury outboard and it wont go into reverse. He said the control handle will go in reverse but the motor wont kick in reverse. he as try to do it by hand back at the motor but still wont kick in reverse. I dont know mean about outboards but i do about inboards my guess is the outboards are the same and i am thinking it has to do with something in the lower unit where the impeller would be. Any ideas I have not looked at it yet but will this weekend and i just wanted some ideas to look for thanks..