Someone added this purple wire .

[MA916870]

Hello , new to the forum . Bought a 1967 Larson from the family of an owner that had passed away . The family knows nothing about the boat or any work that was in progress . A new wire harness was installed from the motor to the front and this purple wire runs to the front and has no connector in the front . The boat has all new gauges with nothing connected . Question ? What could this purple wire be run for ? The engine is I believe a Mercury 1963 650E. Serial # 1598418. . Engine starts on second turn .

 

[dwco5051]

I can't think of any good reason that wire would be there. Maybe the previous owner had a bad key switch and used it to hot wire the starter until he saved enough for a new switch. Purple in normally used to power gauges, etc that need power from the accessory terminal when the motor is running. That is definitely not the case on your motor. the yellow powers the starter solenoid from the key switch.

 

[MA916870]

Thank you dwco5051. Looks like I have more hours of staring and wondering ahead of me . Thank you for you time ! Much appreciated .

 

[jimmbo]

That purple wire is not connected at the other end? How long is it? Are you saying it runs all the way to the Helm?

 

[dwco5051]

I memory isn't what it used to be and there was another use for a purple wire. It would have been used to power the ignition coil on older engines. Either way if your motor is working ok did it had no idea where the purple went and just left it unconnected on one end. The other wire on that stud should be yellow/with a red stripe. Hard to tell from the picture.

 

[MA916870]

That purple wire is not connected at the other end? How long is it? Are you saying it runs all the way to the Helm?

Yes it does . They took the trouble to run it into a wire protector sleeve and all the way to the front of the helm . I was thinking it was to power the gauge lights ?? There is a separate new ( not connected ) wire harness . The purple wire is the only wire connected to the engine . The motor starts and runs fine with the harness that goes to the controls .

 

[jimmbo]

Wired like it is, that wire will only have power when the Key is turned to 'Start/Crank', and no power at 'Run'.

 

[MA916870]

Wired like it is, that wire will only have power when the Key is turned to 'Start/Crank', and no power at 'Run'.

Thank you for clearing that up . At this point I just cant think of any reason it's there other than to activate the solenoid ,however the key at the controller is working just fine. Maybe haven't run into the problem that the previous owner may have had yet . Idk . I appreciate all the help ! Thank you .

 

[merc850]

Disconnect it, leave the yellow connected and try starting it with the key, do the same for the yellow.

 

[MA916870]

Disconnect it, leave the yellow connected and try starting it with the key, do the same for the yellow.

I will do that today . I just have a hard time thinking that they did it for no reason . I'm not done chasing this purple wire yet lol! Thanks again for the help everyone , its really appreciated .

 

[merc850]

On 2nd viewing it looks like they were making a new harness out of separate wires.There's an upgrade in this diagram that simplifies and makes the wiring more secure

 

[MA916870]

On 2nd viewing it looks like they were making a new harness out of separate wires.View attachment 376613There's an upgrade in this diagram that simplifies and makes the wiring

No rectifier ??

 

[MA916870]

All gauges , batteries, devices and switches have been connected and are working without issue . The purple wire remains a mystery . Motor starts with or without it . My best guess is they were planning on installing a push button start at the helm as the wire goes to the solenoid . I would still have to turn the key to the on position however . For now I'm moving on to new impeller and water pump . Thank you all for the help , advice and diagrams .