Shift Interrupter Switch Merc 120

[Mercruiser 120]

Could someone show me the wiring diagram for a 1981 Mercruiser 120 that includes the Shift Interrupter switch that slows the engine down to come into neutral.
Also would you have a wiring diagram for a 1970 Mercruiser 120 because I had to put a new(used) engine in. All the shift cables and outdrive are 1981. I need the 1970 wire colours in case I have to match wires that are different colours, like when I wired the new engine.
Thank you

 

[Maclin]

Your switch may be ok as is. The issue as described can be an adjustment is needed on the lower shift cable, or that the cable is worn beyond tolerances for adjusting. If it comes out of gear finally without turning the engine off then the switch is probably ok, just not getting the nudge it needs at the right time to be in synch with the shifter.

 

[alldodge]

This is an inline 6 but wiring will be the same