Kevin,

I have a 1987 Sea Ray Sorrento S-19 with a 4.3 Liter OMC Stern Drive - with less than 400 hours on the motor.

I just put the boat in the water this weekend – and experienced a slight electrical shock when touching the shifter handle after starting the engine. Given that they are slight shocks I am thinking it may be the ignition switch.

I’ve looked at the boat’s wiring as much as I could see and didn’t see anything that would suggest a short. It all looked in good shape. I also reconnected the boat battery wiring and that didnt work. 

Fuses? Ignition switch? Any thoughts?!

Thank you!

Larry

Hi Larry,

It is probably not your boat’s ignition switch.

The starter circuit goes through the shifter, but not the ignition. Since your problem is still occurring after the engine has started, I would look at connections on the engine.

Your boat motor has a shift interrupter circuit that basically connects your ignition coil to the shift cable. When operating properly, the shift interrupter will momentarily ground the coil during shifting. When not functioning properly, crazy things happen.

The shift interrupter should be on the starboard side of the engine and will have a shift cable connected to it. Chase the wiring from the negative side of the ignition coil to the interrupter to find your problem.

Good luck,

Kevin

Hello Kevin,

I have a 1968 Mercury 200 model, 20 Horse with the breaker type phelon magneto ignition – no switchbox.

I have had it since it was new – my Dad actually purchased it when I was a kid – and always had to manual start it (no electric start kit).

Last year I came across an electric start kit that included the starter motor, solenoid, internal harness and choke solenoid and purchased it – and then let it sit in its box for a year. About a month ago I picked up an external harness and figured I would install and wire the electric start and choke.

I purchased a key switch for Magneto Type Ignition (3 postion – off, on, start with push to choke) and wired everything up. Diagram of switch is below and here is how I’ve set up the boat wiring  for the switch:

• Red wire from harness, B (battery)
• Yellow wire from harness, S (solenoid)
• Black wire from harness, M (ground to solenoid)
• Grey wire from harness, C (choke)

It works fine as far as choking and starting and I am not utilizing the “ignition circuit” terminal as it provides 12 volts when switch is in the on position. However: I’m sure you know this already but the existing kill switch for this motor is located on the lower cowl and has two wires, a salmon color wire and a white wire, that connect to the terminal block (which is where both coil wires attach as well) and of course, to kill the motor you are simply creating a ground in the ignition circuit by pushing in on this kill switch.

I am aware that the upper “M” terminal (Magneto Circuit) on the key switch will complete a circuit to the lower “M” terminal (which is grounded) when the switch is off, thus providing a path for ground in this upper “M” terminal.

Scenario:

I have 2 wires that come off the engine harness (salmon and white) that are supposed to provide a ground to kill the engine but I only have one terminal on the key switch (the upper “M” terminal) that can provide this path. Obviously, I cannot connect both wires (salmon and white) to this terminal because it will create continuity between both coils which will kill the engine.

So here’s my boat wiring question:

How do use this ignition switch to kill my engine? I know I’m being somewhat ridiculous here when all I have to do is reach behind me and depress the engine kill switch mounted on lower cowl. However, I would simply like the ignition switch to be utilized for this as well. Am I missing something like another terminal or can it be done with this switch?

Thanks,

Cecil

Hi Cecil,

If you chase the salmon and white wires down on the engine, you will see that one goes to ground and one goes to the magneto. Connect the one that does NOT go to ground to the open M post on your switch.

If this is not obvious, remove the ground wire from the M post on the key switch, connect the salmon wire to one of the M posts and the white wire to the other.

This will solve your issue,

Kevin

Hey Kevin,

I am going to try the latter (removing the ground wire from the M post and connecting white wire there and salmon wire on other M post). Will let you know.

Appreciate your response.

Cecil
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Hey Kevin,

Well, you are correct!

I assumed the black wire had to be connected to the M post on key switch in order to provide a ground for the solenoid but apparently it is already grounded via the internal harness.

I put salmon wire on one M post and white wire on other M post. Hooked both these wires from internal harness to terminal block, started engine and when I turned key off, motor stopped.

Sometimes I question my competence in such areas and feel quite inferior when situations like this occur..

Thanks again,

Cecil

Hi Kevin,

Could you please answer a question on adding a negative ground bus to my boat wiring setup?

I’ve found metal parts of my boat which are not grounded, like the gas tank, gas deck fill…is grounding these as simple as installing a bus wired to the negative post of the battery and then running a wire from each of these metal parts to the bus?

Thank you, Mike

Hi Mike,

There should be a static ground wire that runs between your deck fill and your gas tank. The gas tank should be grounded to the boat grounding system.

The metal case of AC components should already be connected to the boat’s AC grounding system.

Metal, underwater gear should be connected to a common grounding bus. It should have a single connection point to the battery negative.

Here is a link to ABYC E-11. This goes into detail on how to correctly ground a marine electrical system.

Good luck,

Kevin