How do you remove gears from Johnson 15 hp motor?

If it's the older 50s or 60s motor:

#1- remove shift rod coupler plate on side of intermediate housing w/2 screws, then see inside a coupler with 2 3/8" capscrews. Remove the bottom capscrew. this will allow you to separate the lower unit after you remove the 6 screws underneath the flange and the one long one with it's head up. Seven total.

#2- pull the lower unit down, the drive shaft and the lower part of the shiftrod will come out along with the lower unit. Water pump too. This is a good time to check the impeller. If it's old or partially messed up, buy a new one.

#3- Remove the 6 screws at the c/l of the prop shaft and the whole gear assembly will come apart.

Buy a Sealoc book and learn all about these motors and it will save a lot of grief/expense !!!