Trojan Boat Forum

Looking at the front of my 318, there is a small sender (1/4" NPT) below and to the left of the thermostat housing. There is also another "sender looking" thing directly below the thermostat housing that is bigger (1/2" NPT). The larger "sender" does not have any wires connected to it. What is this larger "sender"? Thanks for any enlightenment you can provide.

Probably the water temp alarm switch. You should pull it out, put in a pan with 1 inch boiling water and see if you get continuity. Or just purchase another one, install it and hook it up. It's a good alarm to have.