71 Thunderbolt 800 Tilt & Trim rewire Question

[hartleck]

I have encountered some bad wiring on the tilt and trim for my Thunderbolt 800. My question is has anyone replaced this wiring before and if so, any advice? I believe there is a plate that I can remove to get to the wiring but I'm not certain. I checked my original Service Manual but it covers everything but this item. Thanks for any help you can give.

 

[merc850]

Re: 71 Thunderbolt 800 Tilt & Trim rewire Question

That is the tilt limit switch yes you can open the cover and rewire it
here's the wiring diagram

there should be a stainless steel clip on the trim cylinder that you can adjust to limit the trim
but I don't see it in your photo.
I would clean up those transom clamps with penetrating oil and a wire wheel and maybe
put some anti-corrosion greases on them.

 

[RRitt]

Re: 71 Thunderbolt 800 Tilt & Trim rewire Question

use sjoo type cable. or, if you prefer, use SJ cable with an Outdoor - Oil resistant rated jacket. You may find that a high grade outdoor extension cord like you use on hedge trimmers has an SJeoo or SJoo jacket. I forget if there is a UV rating or not. You can also go to an electrical supply house and tell them you need some 12awg cable for wiring up an outdoors motor in an exposed, wet location.

 

[Chris1956]

Re: 71 Thunderbolt 800 Tilt & Trim rewire Question

Bypass the bloody thing. The Trim Limit Switches are of marginal use, IMHO. You should be able to unplug it from the main PTT harness and jumper across the trim limit switch connectors. Now the middle trim button will trim and tilt the motor up.

 

[hartleck]

Re: 71 Thunderbolt 800 Tilt & Trim rewire Question

Bypass the bloody thing. The Trim Limit Switches are of marginal use, IMHO. You should be able to unplug it from the main PTT harness and jumper across the trim limit switch connectors. Now the middle trim button will trim and tilt the motor up.

Sounds great, do you think I could get away with replacing that clunky three button switch with a 3 position rocker switch in that case?

 

[Chris1956]

Re: 71 Thunderbolt 800 Tilt & Trim rewire Question

Yes, however it will need to be pretty heavy duty. If you look at the design of the Merc Push button PTT switches, you will see lots of copper contact area to carry lots of current. The up circuit of the PTT unit usually has a solenoid, so you could use a 5A switch or so, which is what the solenoid likely pulls. The down side of a lot of those PTT units have no solenoid, so the switch needs to carry more current than that. Unfortunately I do not know the current value.