Re: temperature switch
As I recall, on a '86 150, the brown wire connects to a thermal sensor which is inserted into the water jacket (2 ea) and held in place with a screw and a little cover thing. Removing the screw and associated plate exposes the switch and it pulls straight out. Follow the wire to where it connects to the wiring harness. The connector is a bayonet and pulls straight out.
The switch shorts out (to ground) when engaged (OT) so the engine should run normally with no horn/light warnings if you pulled the switch out of the water jacket......course for engine safety in the event a temp problem develops, one doesn't want to do that any longer than necessary.
Mark