50 hp Mercury shift shaft adjustment??? Help!!!

Hello gentlemen I am hoping that you can help me on something.
I recently changed the water pump on my engine, while that went smooth something else didnt go so smoothly. I changed the water pump with the engine in nuetral, and when I installed it I had a hard time getting the shift shaft to line up so i turned the prop a little in order to get it to go back into the housing a little and then connected it to the shift shaft and tried to get my adjustment as close to it was as possible. Well when I start the engine in N the props start turning, when I put it back in reverse, just slightly in reverse the prop stops turning, so I know that I have it off although it is just barely off, you barely have to put the throttle in Reverse for it to actually be neutral.
My question is how to ensure that I am in neutral, do I have to take the lower unit off again? Can I just adjust it by changing the postion of the nuts? I have no idea, although I know that it the problem because it was just fine before I did that and it runs great now, its just the cable seem to be a little bit off, and well I cant have that, that means the boat is going to start moving as soon as I start the motor.
I hope all of that makes sense and if it doesnt I would be happy to try to explain it again, thank you in advance for all the help

This is such a common occurance and it happens on a daily basis.-------------------------Take it apart again and put lower unit in nuetral and control in nuetral and reassemble.----------------If you do not like that one then put the lower unit in forward and the control in forward and reassemble.---------------No need to start adjusting anything.-------------Take it apart and reassemble it correctly !!!!

When I installed it the first time the control was in Nuetral, I double checked it. As far as the lower unit how do you put it in Nuetral, if it is detached from the unit? By pushing it up or lowering it?

What year / serial # is your motor ??????-----------The older 50's shift with a rotary motion of the shift rod.----------Post the needed info for folks to help you!!!!!----------------As I said this happens all the time.---------------The lower unit jumps into forward when you are not looking.-------------------So take the lower unit off ---then take the time to see how it works.--------------See which way the driveshaft rotates -------------See and check which way the shift shaft rotates for forward gear / nuetral and reverse. then put it all back together with lower unit in forweard and control in forward.-------------------------------------IT REALLY IS EASY.

I dont have the ser# I am not at the same place as my boat, but it is a 2000. I thank you for your response, I will do the best I can to follow what you are saying. This is my first year owning a boat ever so I dont know alot about them, so I thank you for helping me.

So ensure that both the controll and the lower unit are in forward position and then screw them together, it doesnt sound very hard, although ive seen on youtube where you have to have the lower screw in the same position as it was when you took it off. Is there alot of truth to this or does it matter more than they are both in the same postion as in R N F?
Again I know this seems easy but ive never owned a boat before so I really am a newbie when it comes to marine engines, thank you for your help

They must be in the same position ( when you install ) how you take it apart does not matter.------------both in forward ----------------both in nuetral ---------------both in reverse.---------------Whichever seems convenient to you.---------Check the shift before you install the bolts !!!!

if its like mine (2001 merc mariner 40hp) pretty sure it would be, there is not much adjustment on the linkage about 1 inch. if you wind the nut all the way up the top side of the shaft and then select the gear lever position that closes the gap up the most and then wind the nut back down towards the bottom about half the length of the nut. works for mine perfect every time, the linkage wont close up enough if you have it in the wrong position or the two threaded end will overlap if its wrong. Hope this helps,
Joe

Noticed you were from Ontario. What part?

North of Goderich.

Joe5701 - This information was very helpful. Thank you for posting!!