The wires I have are: 1 red starter cable, 1 tan wire, 1 ground wire to the engine block, 1 red wire to the battery, and 1 red wire that splits into the fuse and into the junction strip. Really need to know which wires go where on the solenoid.
The tan wire is the overtemp warning horn, should have a flat connector on it, connect it to the temp switch near the top of the cylinder head at the back. solenoid has four terminals, 2 large, 2 small. 1 large terminal gets the battery (+) cable *and* the red wire with the inline fuse (it provides +12V to the keyswitch), the other split end gets juice from the alternator for charging the battery. On the terminal strip, it should hook up to red wire coming from the rectifier (small metal canister-shaped device). It's best to secure the battery cable with a nut, then the red wire with a second nut. The other large terminal gets the cable from the starter positive terminal. 1 small terminal gets the white wire from the main wiring harness plug (it's the start circuit), and the other small terminal gets grounded -- just run a black wire from there to any good engine block ground. The small terminals actuate the solenoid, closing the circuit between the battery and the starter motor. To test the overtemp warning circuit, touch the end of the tan wire to the cylinder head with the key in the on position -- steady tone should sound from the buzzer located in the control box. Might want to take a closer look at your tan wire -- maybe the white one yellowed a bit. In '79 they changed that to yellow/red.
Jtex has the right answer if you bought the right solenoid. Unfortunately- the Ford automotive solenoid is an exact replica, but wired different. So less you got the part from Mercury -your going to burn wires as the Ford puts power to one of the small terminals and the Mercury wants a ground to the same terminal as it's ground is regulated by the neutral no start switch.
Red starter wire goes on one of the big lugs, the other big lug gets the wire form the battery and the smaller red wire, the white wire should go on the small lug closest to the battery wire and the black should got to the other small lug. Once you you mount the solenoid on the engine you will be able to tell which side the starter wire and the battery wire are to be placed on the solenoid. The wire from the starter should be only long enough to reach the top lug or the bottom lug just because the way it has to be routed.
