Re: 73 135 hp evenrude temp gauge
Your engine does not have a factory provision for hooking up a temp gauge. It does have a single switch located on the top back of the block. When that switch senses an overheat, it will go to ground, sounding the horn in the control box. This switch is a simple on/off type, without capability to vary resistance-which is what is required for a typical gauge. Most marine dealerships can order a gauge and a matching sensor/sender for your engine. Teleflex makes a number of inexpensive gauges. You would have to adapt that sender to the side of one of the heads with some type of Z-bracket which will hold it in place.