Boat/Engine Harness recommendations

[CrayzKirk]

The boat harness has finally succumbed to the dreaded Mercury wire rot. I've served a long life however the insulation is falling off the cables and i'm going to update it to a newer style control box with integral trim. This is for a pre-1979 boat so it has the old cobra head plug. I have several newer control boxes (newer is relative), an adapter harness that goes from the 8 pin to cobra head, a box from a Mercruiser with a bit 14 pin connector and a number of standard control boxes which would require updating as the harnesses on them are in worse shape than the one I have.

I also have a newer boat with the post 1979 8 pin plug and trim (as a reference point) however the old style trim uses a separate switch for trailing. I also see that I will need to have solenoids on both up and down trim as the newer style is not designed to pull the current to drive the trim pump.

Anyone been this route? Any gotchas to be aware of? I found an installation note with the adapter harness which indicated that it required removing the kill switch in the control box for distributor engines.

All in all, lasting 54 years isn't all that bad. I haven't been inside the control box yet from the 1966 control however from the others that I took apart, it's probably going to be not pretty.

Thanks for any information and experience...

Crayzkirk

P.S. according to the parts that are available, I need a neutral switch and mounting plate. It's gone from the control that I have. Should I just say screw it and buy a modern controller and change the wiring for my distributor engine? Everything is NLA. Really? Why can't they just give us the original mfg part number?

[CrayzKirk]

Looks like Sierra and CDI both make boat side harnesses; they don't look the same however that doesn't really matter. I would really like to have the integral trim switches and tachometer plug in however I've lived with this for a while. Going thru the parts I've accumulated, I found a CDI boat harness. I think I will just cut the old harness a couple of feet from the control box and solder/shrink wrap the CDI boat harness to the old harness. The old harness doesn't have a tachometer lead so I will have that now. I think I will bypass the trim limit switch as well; the switch is either bad or the wiring to it is rotten (requires removing trim mounting bracket from transom and resealing it).

What about control cables? If I opt for a newer style controller, will my old cables still work?

[CrayzKirk]

I'm just going to keep talking to myself... I remove the old controller to get the cables out and the wiring inside is all green and ready to fail. I put a newer (1978?) control box with trim up/down and a trailer button. The harness is in great shape. I also have a similar control box for a Mercruiser setup which has a big round 14 pin plug. The second control box has a second switch, which I used to replace the missing neutral safety switch in the outboard control box. Everything works except the up trim; checked the wiring on the trim bracket and it's corroded. Cut back about two feet and it's corroded all the way.

I don't see a way to get to the switch without removing the bracket...