Re: 1979 Evinrude 200 Temperature and Tachometer Guage
There is a grey wire inside the control box. You can separate the two halves of the control box, and access that wire. It is the factory wire that sends the signal to the tach. You can pull the wire through a hole in the control box havles and connect it to the S terminal on the tach. All you need is a + and - wire at the dash to drive the tach. (and a wire for the light.) Normally, the engine will operate between 143 degrees and around 155. That engine does not have a signal wire to drive a temp gauge. It has a temp switch in each head. They are either open or grounded. Both head switches are open when operating normally. When one (or both) head(s) heat up to 212 degrees, the switch(s) will go to ground and sound the overheat horn in the control box. Once the engine cools off to 175 degrees, the horn will silence. (even 174 is too hot to run the engine normally.) If you want to add a temp gauge to the dash, you will have to order a temp sender and a matching gauge. (not all senders match all temp gauges.) You will have to make and mount the sender to one head with a "z" bracket. Keep in mind that the sender will only show the temp on that one head. The other head cooling system is separate and may/may not run the same temps as the one with the sender. Teleflex makes an inexpensive line of temp gauges/senders.
