Electric Start question 72 Johnson 25HP

[strikeback03]

Does anyone know what the harness for electric start should look like on a 72 Johnson 25HP (model 25E72R)? Mine has it installed, but it looks kinda homebuilt. There is a cable with the wires that go to the ignition switch, and then big separate positive and negative cables with jumper-cable style jaws on the end. There appears to be at least one cut cable in the main group. Should the connections to the battery have been contained in the main harness with the rest of the wires to the switch? Or are these extra heavy gauge cables part of the normal package?

 

[Silvertip]

Re: Electric Start question 72 Johnson 25HP

Did you ever open the hood of your car and look at the battery? Aren't those two cables bigger than any other wires under the hood? The cables with the alligator clips on them are the battery cables. They connect directly to the battery. But trash those clips and put the correct cable ends on or else replace the cables.

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

Well, I've added enough wiring to my car that the stock battery cables are not the largest running around in there, but that is a different story. The current battery cables on the motor look like approximately 2 gauge, while the cable that runs to the ignition switch has 2 ~10 gauge wires in it, one of which is cut and unused. The other wires in that bundle are ~18 gauge, a couple of those are also cut and unused. And the ignition switch has 5 posts, but only 4 are hooked up. I just got the motor and have to redo the wiring to put the battery where I want - does it need really heavy gauge battery wire, or are the ~10 gauge wires in the main cable intended to be the battery wires?

 

[tashasdaddy]

Re: Electric Start question 72 Johnson 25HP

you have to have the atleast #4 for pos cable to starter solenoid, and the ground back to the battery. if you are moving the battery more than 4 feet from the motor you have to enlarge the cables, because of distance resistance in the longer length. if not you will burn up the starter, because of low power. the wiring harness to the ignition switch, on carrys 20 amps. of 12 volts, so they are smaller. you really need a wiring diagram for that particular motor.

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

I have a wiring diagram, but it only gives colors, not sizes. And I was going to put the battery up in the bow to try and get the weight evened out more.

 

[tashasdaddy]

Re: Electric Start question 72 Johnson 25HP

ok, i went out in the rain and looked at my motor, the main pos & neg to the control box look to be #12, the rest look to be #16.

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

Thanks for checking that. This being a 72 25HP, there is no CDI, if that is the control box you were referring to. Wiring diagram shows the neg from the battery running from the terminal through a connector to "Chassis Ground" (dunno if that means boat hull or outboard somewhere). Pos from the battery meets up with a line from the ignition switch at that same connector, and the common line from that runs to the terminal on the starter solenoid.

 

[tashasdaddy]

Re: Electric Start question 72 Johnson 25HP

when i referred to control box , i ment the remote throttle, shifter box.

 

[tashasdaddy]

Re: Electric Start question 72 Johnson 25HP

negative cable runs from battery to a ground bolt on the engine block. the postive cable battery to positve side on starter solenoin. and the pos wire to the ignition switch. the other big post on the solenoid is pos to the starter post.

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

I'll grab some pictures when I get home from work, my shifter/throttle box has no wires at all, just the cabling for moving the levers on the motor.

 

[tashasdaddy]

Re: Electric Start question 72 Johnson 25HP

then we have to set up a dash ignition. there's one on ebay right now #130129693746

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

OK, here is what I have now.

control box. no electronics here.

the wires that were connected to the motor/start solenoid. Notice a couple clipped wires in main cable.

Ignition switch end - spare wires just hanging.

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

Also, can't really see it in that pic, but there is a 5th post on the ignition switch that is not connected to anything.

 

[tashasdaddy]

Re: Electric Start question 72 Johnson 25HP

i don't have a clue as i can't find anything to match those colors.

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

Yeah, they don't match what is in the wiring diagram, which is why I was assuming this is a home-built setup and wanted all the proper wire sizes so I can redo it correctly.

 

[tashasdaddy]

Re: Electric Start question 72 Johnson 25HP

the power and ground from the switch size of the green on the switch the rest can be the smaller size.

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

Do the cables from the battery (second picture) look the correct size?

 

[tashasdaddy]

Re: Electric Start question 72 Johnson 25HP

fine for a 25.

 

[strikeback03]

Re: Electric Start question 72 Johnson 25HP

I'd hope so, they're larger than the starter cable in my car.

Thanks for the help. It works, gonna take the boat out this afternoon and see if battery at front vs back makes much difference before I start drilling holes for a final install.