MEP-002A Starter lock out switch bypassed?

New to the forum, been reading for a while on my new to me 002A. Love this forum, full of awesome information!
I'm having an issue with my starter not dropping out when the engine is running. I checked the starter lock out switch and it works correctly. I get continuity with the engine off and none when the engine is up to speed.

On the control panel side of that barrel connector, I do get continuity between the two pins.... Makes me feel that the previous owner bypassed it somewhere in the control box. I tested for continuity from either of the pins to the terminal strips and I get good continuity on a ton of terminals.

What direction do I need to go to diagnose this one? I feel someone bypassed the lock out on purpose.

So, is it staying engaged while its running or is it grinding after its running and you go to start again?
If its continuing to be engaged after the master switch goes back to prime and run, its more than likely A1 relay assembly. It has a diode behind it and if it fails will continue to keep the starter engaged after its up and running.

The starter stays engaged while I am holding in the start position while I wait for the oil pressure comes up. Stays engaged until I release the switch back to prime and run. The lockout switch is not disengaging the starter when the engine is up to speed.

Matter of fact, I can start the engine with the starter lockout switch barrel disconnected.

View attachment Scan_0001.pdfI hope you can read this. On the left side is the diode Jamawieb spoke of. Check it. On the right side is the first place I would look for a jumper to bypass the S7. I would hook up a wire from TB4-3, to TB4-12, 13 or 14.

Guyfang said:

View attachment 759928I hope you can read this. On the left side is the diode Jamawieb spoke of. Check it. On the right side is the first place I would look for a jumper to bypass the S7. I would hook up a wire from TB4-3, to TB4-12, 13 or 14.

Click to expand...

Okay, I will check for a jumper where you noted.
After studying the wiring diagram for a while, I plan also testing the wires at TB4-3 and which ever P55D is on for shorts. I now have the suspicion someone twisted the crap out of J16 connector for S7 and maybe twisted the leads together, thus shorting them together.

I have often seen that happen. Take the plug apart, and take a look see.

And there it is. My suspicions were correct. Used some electrical tape to separate the wires, adjusted the lockout a tad... boom it works. Appreciate the help guys!

Like I wrote, very common problem. Good work finding the problem! Now, how is the machine reacting? what will it do? What will it not do?

Taquin said:

And there it is. My suspicions were correct. Used some electrical tape to separate the wires, adjusted the lockout a tad... boom it works. Appreciate the help guys!

Click to expand...

That calls for a clean up and resoldering and a small piece of heat shrink over each pin.

Glad you found the problem.

Guyfang said:

Like I wrote, very common problem. Good work finding the problem! Now, how is the machine reacting? what will it do? What will it not do?

Click to expand...

Yes, it is working as designed now. Hold down switch in start position, it starts up, the starter disengages when the engine fires up.