Oman MDJE red reset button

[Perdiem]

Hello! The red emergency reset button popped out while the generator was off so it wouldn’t start the next morning. I pushed it in and all was well for a few days and then it popped out - again while off.

Now it won’t stay in when I press on it. And the genset won’t start if I hold it in.

I think it should only pop out if there is a low oil pressure or high temp condition while running.

Is there a way to bypass it so we can stay out another week??

There isn’t much room above the control box so I can see in there but would have to remove it all together to work on things in there.

Many thanks in advance....

[sy_gilana]

Your centrifugal switch is stuck in the closed position, probably frying the heating element in the ER.


Switch off battery, check for 0.020" inch (.51mm) clearance in the contacts.

Allow to cool, try a reset.

If that does not work, your ER is fried.

To bypass, AFTER setting the gap, you can strap-up the stop solenoid plunger, or remove it, or wire it directly to battery through a switch.

To shut down you must manually push the lever to the injection pump down> or if you did the electric switch option, switch it off.

YOU WILL HAVE NO SAFETY CIRCUITS IN OPERATION!!!!!!!

[Perdiem]

Thanks for your reply. You are definitely on the right track. I adjusted the centrifugal points as the generator would stop when I released the start switch. Not having feeler gauges, I just made them a bit closer. Maybe I made them too close!

I adjusted them Friday afternoon and the genset fired right up. It started fine Saturday morning and the Saturday afternoon the reset button was out.

Does it make sense that if the points were shorted overnight that it would run the next morning?

Am I to understand that if I hold the stop solenoid up the engine will run??

This fall I will be in the market for a lightly used Northern Lights generator!!

[sy_gilana]

Originally Posted by Perdiem

Thanks for your reply. You are definitely on the right track. I adjusted the centrifugal points as the generator would stop when I released the start switch. Not having feeler gauges, I just made them a bit closer. Maybe I made them too close!

Take a vernier caliper or something that can measure half a mm, or 20 thou, then use that as a gauge. It is important.

I adjusted them Friday afternoon and the genset fired right up. It started fine Saturday morning and the Saturday afternoon the reset button was out.

It probably was closed some of that time, battery voltage goes through the Cent Sw, then the ER, to the sensors, and if they ground, a circuit is made, the heater (inside the ER, a bimetal strip) heats up and pops the red button.

Does it make sense that if the points were shorted overnight that it would run the next morning?

Well, it could, if the contacts were closed while warm (and stopped) and then opened when cooled.

Am I to understand that if I hold the stop solenoid up the engine will run??

Absolutely

This fall I will be in the market for a lightly used Northern Lights generator!!

I think you should think twice. The MDJE had engines built by Onan themselves, and they are fantastic. They need to be nursed. Mine is a 1978 model, with 35000 plus hours.

There is a web site called SMOKSTACK, you should spend some time there.

[Perdiem]

I held the stop solenoid up and it wouldn’t fire. I haven’t adjusted the points yet but the engine should run while the start switch is operated no matter the status of the points, right?

[Ericson38]

I have an 8kW MDKD and bought and adjusted my solenoid by reading this great post.

https://www.smokstak.com/forum/showthread.php?t=89953

[sy_gilana]

Originally Posted by Perdiem

I held the stop solenoid up and it wouldn’t fire. I haven’t adjusted the points yet but the engine should run while the start switch is operated no matter the status of the points, right?

Right. The start switch bypasses the Centrifugal Switch. This is according to design and according to the start up sequence.

If your engine is not running its something else.
It needs compression, and fuel at the right time and amount. None of those have changed.
Make sure that the stop solenoid is not pushing down on the small lever of the Nikki injection pump, it does not operate the governor linkage.

Fiddle with the levers on the injection pump.

Have you messed with anything else? like fuel filters, or fuel pump, etc, you might just have air in the system.

[Perdiem]

I just noticed your reply (thanks!). I'm home now with better internet for a couple of days dealing with other issues.

I've not changed anything else. I can always tell if it is just a centrifugal switch points issue because the generator starts but does not run after the start switch is released. When it is a red reset button issue it doesn't even try to start - it just cranks over.

I've adjusted the points.

I printed your last response and am leaving for the boat to try and figure it out.

[sy_gilana]

Do you have the wiring diagram for that genset?


There is nothing else electrical that will stop it running...

All stops end at the stop solenoid.

[Perdiem]

Thank you for your patience in this. I could not get the engine to fire. Common sense tells me that it won't fire as long as the reset button is out - and it is permanently out - or am I still wrong here.

I did not have a wiring diagram but I found the Onan Marine Training Manual 934-0405 MCCK, MDJA, MDJC, MDJE, MDJF (Generator & Controls) on line and it has lots of information including wiring diagrams and a description of the operating sequence (which relays operate and when etc).

I will take the information you have generously given along with the relevant pages of this training manual and get a local mechanic familiar with these things to take a look.

For anyone interested, here is the link:
Onan Marine Training Manual for MCCK, MDJA, MDJC, MDJE, MDJF (Generator & Controls): 934-0405: Page front

Pages 131 - 137 cover the diesel control circuits.

[sy_gilana]

Great Link, I wish I could download the whole thing.

I am certain, even after looking at the 612 series wiring diagram in the site above, that there is only one Rome, to which all roads lead. Or, no matter how many safeties you have, they all land up at the stop solenoid, or the fuel shutoff system. On the MDJE 612 with the YD reg...which is what I have, there is a vertical stop solenoid, it pushes down on the fuel lever sticking out the side of the injection pump. At the end of that lever is a ball joint that is connected to the governor control system. Halfway along the lever is a small shaft bolted on, this is where the fuel shutoff solenoid pushes unless energized.

IF the solenoid is removed, and the lever is allowed to rise under the direction of the spring balanced governor arm, the engine MUST start. There is nothing else preventing it. Having said that, all the NORMAL diesel requirements must be met, Compression, Timing, Fuel....

Check that when you move the governor arm, the lever on the fuel pump moves...maybe you have a cracked ball joint...

[sy_gilana]

Also...Make sure your exhaust muffler is not full of water creating back pressure. If you can drain it, do so, and, shut the seacock until it fires....

[Perdiem]

Great Link, I wish I could download the whole thing.

I found it in one file. I’m on my phone and I saved to the iBooks app so I’ll always have it.


https://ia800901.us.archive.org/30/i...al_07-1979.pdf

[Perdiem]

Fixed!! And thank you! I took out the main engine start battery and loosened the water tank and moved it over so I could get right in there and see. The ball joint was cockeyed and jammed, probably from me not lifting the plunger straight up. I should have done this from the start and I would have wasted less of your time.

Two final questions:
- I wired the stop solenoid through a switch and a 10 amp fuse. Can it be powered up for a half a minute or so before the generator starts without burning anything up? The plan is to go to the lazerate and pull the switch, then go into the boat, do the 20 second preheat and then start the generator. I assume it is OK because the solenoid is powered up the whole time the gen is running but I have been wrong before here.

- I left the original wires on the solenoid and tied my new battery and ground wires over them. This puts 12 volts into a suspect control box. Is this a concern? Would putting an insulator between the points lessen any concern?

Again, thank you for sharing your knowledge on this.

[sy_gilana]

Originally Posted by Perdiem

Fixed!! And thank you! I took out the main engine start battery and loosened the water tank and moved it over so I could get right in there and see. The ball joint was cockeyed and jammed, probably from me not lifting the plunger straight up. I should have done this from the start and I would have wasted less of your time.

Two final questions:
- I wired the stop solenoid through a switch and a 10 amp fuse. Can it be powered up for a half a minute or so before the generator starts without burning anything up? The plan is to go to the lazerate and pull the switch, then go into the boat, do the 20 second preheat and then start the generator. I assume it is OK because the solenoid is powered up the whole time the gen is running but I have been wrong before here.

- I left the original wires on the solenoid and tied my new battery and ground wires over them. This puts 12 volts into a suspect control box. Is this a concern? Would putting an insulator between the points lessen any concern?

Again, thank you for sharing your knowledge on this.

If you are doing a bypass with a separate battery, DO NOT inject 12v into the system!

Disconnect the original wires, put on the new 12v supply as described, this is a "Get you home" temporary solution, it is NOT a fix.
You will have no safeties.

You need to repair, or replace the safety relay. Try eBay.