Mystery - emergency kill switch-starter solenoid

Yesterday I began helping my brother with his Larson/Volvo Penta/4.3GS and I ran into the following that has me puzzled. The boat also has an emergency kill switch mounted near the shift/throttle lever.

Hopefully someone can steer me with some advice.

The following test were performed with the shift lever in neutral and the neutral button out with the lanyard in the emergency kill switch.

First we have voltage at the ignition switch B terminal in the off position. We also have voltage on the ignition switch I terminal in the run position and on one terminal of the emergency kill switch but we are not getting any voltage on the purple wire at the coil/starter/alt. And we have voltage on the ignition switch S terminal in the start position and the starter spins the engine and the engine will fire but dies when the key is released to the run position.

I'm stumped because the only way that I can get voltage on the purple wire to the coil with the ignition switch in the run position is to remove the lanyard from the emergency kill switch. But doing that sends voltage to the starter solenoid and engages the starter.

I'm told that the starter was recently replaced with an automotive type rather than an OEM. The starter only has three terminals rather four as shown on all of the wiring diagrams available through this forum.

Any pointers would be a great help at this point and if I need to supply more info please just ask. My brother would rather not bring the boat to a marine mechanic until we exhausted this resource.

Thanks!

Re: Mystery - emergency kill switch-starter solenoid

We also have voltage on the ignition switch I terminal in the run position and on one terminal of the emergency kill switch but we are not getting any voltage on the purple wire at the coil/starter/alt.

Click to expand...

Ayuh,... By-pass it, it's open, rather than closed...

I'm told that the starter was recently replaced with an automotive type rather than an OEM. The starter only has three terminals rather four as shown on all of the wiring diagrams available through this forum.

Click to expand...

Put the Right starter on it, you Need the other terminal...

Re: Mystery - emergency kill switch-starter solenoid

First I'd like to say thanks for responding, but I'm wondering if you might be able to explain these two.

1=Testing for resistance through the emergency kill switch it appears open when the lanyard is in place and is closed when the lanyard is removed. I thought this would be proper operation for the switch.

2-About the starter, I understand that it was replaced with a non OEM part but I don't understand the need to supply a constant 12 vDC from the I terminal on the ignition switch. Isn't that the purpose of the S terminal and the starter relay?

Re: Mystery - emergency kill switch-starter solenoid

joel.roy said:

First I'd like to say thanks for responding, but I'm wondering if you might be able to explain these two.

1=Testing for resistance through the emergency kill switch it appears open when the lanyard is in place and is closed when the lanyard is removed. I thought this would be proper operation for the switch.

2-About the starter, I understand that it was replaced with a non OEM part but I don't understand the need to supply a constant 12 vDC from the I terminal on the ignition switch. Isn't that the purpose of the S terminal and the starter relay?

Click to expand...

1) Are you doing this test with the wires removed from the switch. If you don't remove at least one wire, you will get an erroneous reading. For an I/O this needs to be open with the lanyard removed. Opposite is true for an Outboard.

2)Someone wired up the starter incorrectly when they didn't have the 4th terminal on the solenoid. sounds like they wired up the wire that goes to the coil to the start terminal of the solenoid thereby engaging the starter when just the ignition is turned on.

Re: Mystery - emergency kill switch-starter solenoid

The four terminal starter has both an S and R terminal. The S terminal is active when the key is in the START position. The R terminal bypasses the "ballast resistor" in the ignition system harness that feeds the coil during engine cranking so a full 12 volts is applied to the coil. After engine start the ballast resistor goes back in-line to drop coil voltage to safe operating levels. By installing the wrong starter you lost the R terminal and therefore the ballast resistor circuit is open after you let go of the key during startup. The engine therefore dies. The kill switch is either the wrong one or you are measuring wrong. With the lanyard in place the kill switch is closed (continuity) so the ignition system is live. Pull the lanyard and the engine dies because you lose power to the ignition system.

Re: Mystery - emergency kill switch-starter solenoid

Thanks for additional info on both issues.

I checked the emergency kill switch completely removed from the boat, I just don't understand how this could have worked in the past. Unless the internal spring could have somehow flipped.

I thought the use of the ballast resistor was only for Pertronix type systems, but I'm no expert on these matters. I just reviewed the wiring diagrams and I see it now.

Thanks for the explanation and advice.
Joel