I have a 1991 Evinrude 48 Special. I'm wanting to add a temperature gauge. From the motor, the wire to the over heat buzzer is tan. There is a tan pigtail (unused) that has electrical conductivity to the control box. The question is, is the extra tan pigtail, the lead for the gauge? And.... do I need to disconnect the over heat buzzer, or can I just add the sender in the cylinder head, connected to to the pigtail, and add the gauge, tapped into the the buzzer.
I never found those high temp warnings to be very useful. Never go off until it's too late.
I'm thinking the same thing you are about a temp gauge. Looking at eBay there are a few options, mostly water temp gauges but I think they could also be used for head/block temp. Check this out. Cheap enough if it doesn't work. copy and paste, remove the spaces.
Are you sure the wire coming from your control is for temp. Check a schematic, it just might be for a tach.