Mercury 50 (500) helt wire up retrofitted electric starter

[modopopcorn]

Hi guys! My last outboard was beyond salvation so I bought a new project to invest all my hard earned money into.

It's an 1970 Mercury Thunderbolt 500 in pretty good condition apart from the issue with stalling when shift into gear. Hopefully this has been sorted out as I cleaned out the carburetors today and the jets was almost clogged shut.

However, this is an 500M model, i.e. it didn't come with an electric starter from the factory, the previous owner bought this outboard with a boat in 2003 and retrofitted an electric starter on it, but when I went to pick the motor up earlier this week al the wiring was disconnected and the gentlemen I bought the motor from couldn't remember exactly how it's supposed to be wired correctly as it's a couple of years since it was unmounted from his boat and his memory was failing (poor old man).

The wiring loom came with four larger wires where I suppose the long red and black wires are supposed to be connected to the battery, however I can't really make out where the yellow/black and short black is supposed to go. Also there's another black large wire connected to the rightmost post on the starter solenoid.

All this is connected on a second solenoid that's connected to a wireless receiver that makes it possible to start the motor without actually being next to it (worthless feature I know but still kinda cool).

I really need help sorting out how to connect all this wiring and would greatly appreciate any help and advice I get.

 

[GA_Boater]

Remote start on an outboard? That's a new one. I would chuck that thing.

This should answer the other questions, but wire colors may differ slightly.

 

[modopopcorn]

Thanks GA_Boater, this helps me a lot! A couple of things I need to sort out though.

Sure, I'll discard this remote starter thingy. But this diagram doesn't match my set up 100%.

I'm buying this ignition-switch tomorrow to replace the secondary relay and all the rest of the wires that's connected to it.

As I don't have the wiring loom with the seven different connections I have to wing it a bit. I've attached a diagram of how I think it's supposed to be wired up but I'm far from certain that it's correct. What do you think? also, I suppose the wiring between the starter solenoid, the starter and the battery should be on the thicker side?

 

[GA_Boater]

Your way will have no choke or neutral safety switch.

What do you have for the boat-side harness between the motor and remote and the internal motor harness?

 

[modopopcorn]

As for choke it online has a manual lever on top of the cowling next to the manual pull-starter, the motor doesn’t have a choke solenoid as it didn’t Coke Witch electric starter.

The same goes for the neutral safety switch, there should be a safety feature that presents the manual puls-starter from being pulled when in ger but it has been removed by a previous owner.

would you say that my diagram is correct aside from your concerns?

 

[modopopcorn]

As for harness it doesn’t have much, I’ve included all the circuits and wires in my diagram.

 

[modopopcorn]

I've installed the wiring today alongside a new ignition-lock. Everything's connected as in my diagram above aside from that I didn't connect anything to the S-terminal on the ignition lock as the boat doesn't have any electric equipment at all.

The connection for the kill switch didn't work as anticipated, I could hear spark grounding in the connection when I started the motor and the switch wouldn't kill the motor, only way to stop it was short out the pins using a flathead. I removed the broken and frail plastic inside the connections and instead I pulled the wire from the control box inside the cowling. There I connected the black wire to ground and the white together with the orange wire from the switch box.

Now all I've got to do is pray to all the sea gods that the stalling issue is gone once I put the boat in the water.

Thanks once again for the help GA_boater, the diagram was a lifesaver