1961 Johnson 75HP old boat to newer boat electrical system intergration?

mnboater26

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I purchased an old boat, and then found out that it was even older than I had originally been told, 78 but really a 61, and the motor that was on this craft is a 1961 johnson V4 75 HP Electric. Needless to say the Old boat just needs more work that I am looking to put into a project right now, so i am taking the motor that runs well and placing it on a newer boat(71 Larson). The issue I am running into is that this older Johnson's electrical system (wire harness running from the motor to a box mounted under the rear splash deck, containing the starter soliniod and other components that are required for the motors charging system) is not compatible with the newer boats "plug and play" setup.

Is it a waste of time to try and use this box and try and integrate it into the already in place system that is in the newer boat? or does anyone have any info on a way to convert whats in that box to what I need to plug into the new boats setup.

ANY info on this would be a great help..

Thank you all for looking
 

F_R

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Re: 1961 Johnson 75HP old boat to newer boat electrical system intergration?

Not being familiar with what's in the newer boat, you certainly would be best off by using at least the junction box and engine cable. From the junction box forward is just wires, nothing really special, so it would seem reasonable that you possibly could use something that is already installed. Color codes are probably all wrong. Also, the dash switches might be wrong too. Is it really that big a deal to run the correct cable forward?

Does your '61 have the alternator? If so, you certainly need the junction box on that one.
 

mnboater26

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Re: 1961 Johnson 75HP old boat to newer boat electrical system intergration?

I was informed from a gentleman that has the exact motor I do and he is the one who told me that, without this separate box from the older boat/motors electrical setup. the motor will not start with electric start, nor will the charging system work. as far as what is in the newer boat and connected to the plug and play setup I am unsure if there is another junction box similar to the one in the connected to the older boat or not. I would assume there would have to be, but weather or not it is anything like the old one, I don't know, as I have been able to get back to look there.

as far as the wires from the box to the main council running all the electrics in the new boat, I would rather not have to re-run anything, I would just like to some how integrate the old system with the new. on an upside of the situation. the new boat and the old boat are the same brands, both Larson's, and both older than 80 so they may both have the same color wires/systems set up in them. but again, i have not had a chance to check it out.. I will today and post more info.

thank you for your reply, and any other info/ideas you may have is greatly appreciated.
 

F_R

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Re: 1961 Johnson 75HP old boat to newer boat electrical system intergration?

The engine wiring in the boat has nothing to do with it being a Larson or anything else. The engine wiring is part of and comes with the engine. There is a world of difference between the old '61 and a '71.
Try to use as much as you can of the junction box assy that belongs to the motor you intend to run. Heck, a '71 doesn't even have a junction box.
 

mnboater26

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Re: 1961 Johnson 75HP old boat to newer boat electrical system intergration?

Yeah I looked at the new boats electrical setup, and no junction box at all. Any ideas on how to keep the old junction box yet still use all the pre-existing wiring that the newer boat has? I would hate to have to rip it all out and start fresh.
 

F_R

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Re: 1961 Johnson 75HP old boat to newer boat electrical system intergration?

Personally I would rip it out. But if you insist, see my previous post. It was based on cutting the present cable and wiring it into the junction box. Are you electrical literate and can you read a wiring diagram? Or know somebody that is?

Actually it's kind of a shame to cut the cable. Somebody could use it and would give you some $ for it on e-bay.
 

mnboater26

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Re: 1961 Johnson 75HP old boat to newer boat electrical system intergration?

The small junction box and the old motor electrical can easily be removed from the old boat. it is really all the existing wiring in the newer larson that I wish not to have to replace or remove. I just want to splice into it. There has to be a way to intergrate what is there to what this motor needs to run properly.

And yes I am electrically illiterate, as well as know a guy who lives in my building that is an electrical mastermind, and has already taken a look at what the old boat has, and told me that we should be able to get it to work with the new system. I am trying to get more info, especially if there is someone that has tried and has successfully done this integration before. but if I cannot find any info on it. I would at least like a wiring diagram of both boats. but I am not sure where to even start to look for those.
 

F_R

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Re: 1961 Johnson 75HP old boat to newer boat electrical system intergration?

We don't know for sure which '61 75hp model you have. There were models with a DC generator, an AC alternator, and no charging system at all. Nor do we know what motor was on the Larson, which would determine what diagram would apply to that one.

Wiring diagrams are included in all original OMC factory service manuals. You really ought to get one for your motor anyway. Check e-bay or you can get new ones from outboardbooks.com/

With the diagram for your motor your friend can figure out the rest.
 

mnboater26

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Re: 1961 Johnson 75HP old boat to newer boat electrical system intergration?

the exact motor I am working with is a 1961 Johnson 75 V4 Electric # V4S13 it is the one with the magneto not the distributor.
I hope that helps.
at this point from what I am getting from this and a few other older boat forums. I am looking at having to use the old wiring/ignition. or buy a newer motor.

So the sleek fancy black ignition box/throttle control gets replaced with an older more Modest, not so sleek setup.
 
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