"I have a 1975, 115 Johnson. a
"I have a 1975, 115 Johnson. and just recently went into it to clean and lube. It has a lower and upper half.
If yours is like mine, first have the shift in neutral and the idle leaver full up.
There are three phillips head screws holding the lower half. Note that the throttle cable is secured by a barrel knob that fits in a socket in the lower half. this may give some resistance when removing the lower.
Be sure not to do anything that moves slides on the cables once the covers are off.
The upper the shift lever is removed by an allen screw in its center and removing the idle lever.
Detach the command center from its mounting. You may run into snags depending on how the wires were run. I had to remove the tach and kill switch wires. Remove the arm rest pad, three screws. There are three screws on the back side of the center holding the upper.
The ignition is behind the upper cover. There are a number of wires connected to the switch. Besure and label. I have a shop manual with a wiring diagram. If you need more info.
I found the factory grease had completely hardened in the plastic cam piece and had to be scraped out. Hope this helps. It looks a lot more complicated than it really is.
Oh, nearly forgot. There is one trap to be aware of...the detent spring loaded ball that engages the shift cam. The plastic cam I mentioned is sandwiched between the back side and the upper plate. Not sure if you have to remove it to access the switch. If you do, the detent ball will pop out. To replace if during assembly, put the cam in first and remover the cover plate holding the detent ball and spring, one screw. load the ball in first and push the spring in, ball side first. It is pretty stiff so be careful.
See
http://www.marineengine.com/discus/messages/12478/115655.shtml"