1973 Mercury 850 wiring

[plane_crazzy]

Hi, new guy here. Had a boat given to me and am trying to get it operational. It has a 1973 Mercury 850 outboard on it. The wiring from the control box to the engine has problems. The wires to the battery and battery to motor are all needing replaced. Is that section of wiring what is called the wiring harness? I would need everything from the control box, to the battery and then to the socket on the side of the motor. Ive looked at parts sites but cannot be sure if the wiring harness is what I need or not. Any help would be appreciated. Also, I have not yet gotten a manual for the motor, are there any free wiring diagrams available online to get some idea what I am looking at/for?

 

[Barnacle_Bill]

Re: 1973 Mercury 850 wiring

Free manuals area as rare as hen's teeth. Try your local library.

 

[plane_crazzy]

Re: 1973 Mercury 850 wiring

Ok my mercury 850 s/n 3503564 needs new wiring from the motor to the control box. I am assuming that is a wiring harness assembly. When I look at sites to order it, some give more then one type of harness available, with no difference stated. How can I be sure of which part number harness that I need?

 

[cannonford57]

Re: 1973 Mercury 850 wiring

with an engine that old you want to run a compression check first,thats a starting point,the harnesses are available from an aftermarket company cdi comes to mind.check the website.......the only thing about that engine is if you get both harneses,you already have more in parts than the engine is worth...then you have to consider crankcase pressure which you cant confirm until you spend this money just to get it spinning over....if cc presure is bad(which wouldnt be a big suprise) your done......nothing on that engine is cheap,especialy ignition parts,figure carbs have to be soaked and cleaned,labor and kits could be 250.00 or more and that my friend is more than the motor is worth in running shape......not trying to bust your bubble but i do this everyday.look it up on nada.com......sentimental value is one thing but it has a limit......good luck to ya.

 

[plane_crazzy]

Re: 1973 Mercury 850 wiring

Can appriciate honesty. Just found a wiring diagram, so I am going to try and patch up the current harness and see where I am. Local Marina will put in a new impeller, internal lube, and rebuild the carburetor for about 500 dollars. If that is all that is required, then I dont think I can find anything comparable for that amount of investment.

 

[cannonford57]

Re: 1973 Mercury 850 wiring

dont make any plans until you see what you run into on the harness.everything ya touch is gonna fall apart and a good (piece) of wire to splice onto is gonna be rare and elusive......but as always, myself and all the guys wish you well.....

 

[cannonford57]

Re: 1973 Mercury 850 wiring

and its the carb X 2,there is 2 on that engine.