Power Trim (70s Model 1)

[BB63QM]

I am converting from manual trim assist to power trim. I have managed to find all the OEM parts (pistons, brackets, hoses, pump, 3-button, wire run, limit switch, etc), but am lacking a diagram or better yet, a set of pictures, that shows how the wiring hooks up.
Specifically and for instance (there may be more), there is a 90A fuse in the parts diagram, but it is not shown on the wiring diagrams I have (attached), at least not force single-solenoid model (unless the “coil” notation is electro-see for fuse…see attached…and even then I’m confused).

In the twin solenoid model (see diagram), the 90a fuse bolts to the positive terminal on the (starter) solenoid and then to the positive lead from battery. This makes good sense, so I assume that this is correct, but I have yet to find anything that confirms.

Also, in the single solenoid diagram, there is a terminal block bisecting the green wire…is that to be somewhere on the pump unit, or somewhere else?

Thanks for your help.

Gary

 

[Chris1956]

The left most image is how my '77 Merc 1500 was wired.

I do not remember a fuse in the circuit. The terminal block is used just so the PTT motor wiring can be removed, for PTT motor repair.

Switched (primary) power to the solenoid is less than 5A. Power to the down circuit is direct from the switch to the PTT motor. Maybe it is 15A or so. The 90A fuse was on the MerCruiser PTT pumps, which were pretty similar looking.

The trim limit switches usually break. I would make sure your's works, before configuring the wiring.