Re: 1972 65HP Johnson. Shift wiring advice.
Be very careful when pulling the "bulb" part of wire up, into the hole in the exhaust housing adapter. The midsection shift wiring harnesses are no longer availble, so replacing one if the wires break isn't easily done. If if you do find an NOS part, you will pay dearly for it.
On my motor, I chose not to pull the wiring up into the hole completely for this reason. What I did, instead, was to seal the hole around the two wires with high temp silicon. This prevents exhaust from getting into the cowl (very important!), but doesn't risk the wires.