1978 johnson 25E78C wiring help!!! Please!!

[fragglewhat]

Ok so this is the issue I am having. My neighbor has a Johnson 25E78C motor, we are trying to connect the wiring to the ignition switch and we are having some issues. The motor did not come with an ignition switch so my buddy bought one from the local boat dealer, it is a Mercury switch, Quicksilver 87-88107A 5. It has 6 wires coming out of it. Yellow/Red stripe, Yellow/Black stripe, Black/Yellow stripe, Red, Black(with two black wires coming out of it), and a purple wire. My question is can I use this ignition switch to start the Johnson Motor? I have a good sense of mechanical know how as I am a Mechanical Engineer. I just don't know how to wire this up. What wires do I need to use and where on the motor will they go. Any help or advice will be greatly appreciated. He also stated that the motor is not electric choke. It is a remote motor. Thanks again in advance for any help.

 

[Joe Reeves]

Re: 1978 johnson 25E78C wiring help!!! Please!!

What are the terminals marked on the back of the ignition switch? They should be.. B, M, M, A, C, S (yes, two M's). And if so...........

M - Normally a raised boss terminal = Powerpack kill circuit (Black/Yellow)
M - Normally a regular flat terminal = Powerhead ground (A single black wire)
A - Accessory terminal = Normally a "purple" wire. Anything you want 12v going to only when the key is in the ON or START position.
C - Choke terminal = Normally a "Purple/white" wire.
S - Starter solenoid = Normally a "white" wire.
B - Battery voltage terminal = Normally a "red" wire.

Your color code above is not listed in any of my manuals so you'll need to trace them out. Being a mechanical engineer, that should present no problem. Good luck.

The color coded wires that you speak of..... Are they leading "from" the engine in a wiring harness?

 

[fragglewhat]

Re: 1978 johnson 25E78C wiring help!!! Please!!

No that is what is so damned confusing, the wires I mentioned are coming out of an ignition switch, the keyed switch. The bottom doesn't have any letters marked on it whatsoever, it is just like the wires are molded into a hard resin coming out of the switch. The wire colors are what threw me off. I will post pics in a few minutes that I took last night of the switch. Thank you for anymore help you can offer, it is greatly appreciated.

 

[fragglewhat]

Re: 1978 johnson 25E78C wiring help!!! Please!!

Here are the pics

 

[Joe Reeves]

Re: 1978 johnson 25E78C wiring help!!! Please!!

It would be best if you return that switch for a refund as it is only going to cause confusion.

The ignition switch you need to be compatable with the 1978 25hp Evinrude is (OMC or Bombardier) part number 508180, or (Sierra) 18-1802. This switch would be available at this site, any Evinrude/Johnson dealership, various marine stores, etc.

Hopefully you do have a factory wiring harness leading from that engine to the ignition switch so as to have the properly color coded wires, and also the electric starter, starter solenoid, choke solenoid, etc? If not, you'll need to go into deep detail as to what you do have fin order for us to guide you.

 

[boobie]

Re: 1978 johnson 25E78C wiring help!!! Please!!

Agree with Joe +2........ Take the switch back and get the proper BRP one.