1979 85 hp model 200840R

I am installing this on my boat there is a black plastic box that has all the wires coming out is this to go in the engine or bolt on the transom as it looks like a solenode of some kind and has the ptt wires on there as well also has positive and neg large ones that look like go to battery but motor came with 2 shorter ones that look like battery leads as well as the ptt there are3 smaller wires on there remote box has around red plug which I am sure goes in the motor don't want to wire wrong and cause a big burn out ,I might mention I live in Aussie down under and when I matched up model number It says it is a 200 hp but is a 85hp this will teach me for switching from Mercury

Re: 1979 85 hp model 200840R

As you noted, the model number is from a 1978 200 hp engine. The trim units were the same, whether an 85 hp or a 200. The trim solenoid box was a rather large, bulky design but worked. It came with it's own heavy duty leads, which connected to the battery just like the engine's starter leads. Most of them got mounted under the rear splashwell of the boat. The current for the trim down movement flows direct through the trim switch in the handle of the control box. The up movement requires more current, so that current flows through the solenoid in the box, as is activated by the up movement of the switch in the handle of the control box. That box should have three wires going to the trim motor on the engine. The black wire is ground, blue is the up and green is the down. There also may be an additional pair of wires which would be wired from a trim sender in the transom bracket and would activate a gauge on the dash. Originally, the factory wiring diagram was glued/mounted inside the trim box, on the back of the front cover. There is a 20 amp fuse in this box, same on as in the wire harness of the engine. Typically, the control box will have a pigtail wire/plug about 2' long, dangling from the control box handle. This wires from the trim box switch through another harness to the trim box.