NL M673 issues

[PJS1554]

I have a couple of issues with my generator. Possibly interrelated?

Recently while running the generator while under load it suddenly stopped. To the best of my knowledge it did not over heat as there was water flow before it stopped and the temp gauge on the panel was 185 degrees. The generator will restart if the glow plug switch is held down but if you release it the unit shuts down. It will run loaded or unloaded for about 45 minutes. It has normal out put voltage and will carry the load no problem.

Second issue is the alternator slowly climbes to 15-16 volts on the control panel gauge. I have verified the output with my fluke . I have replaced the voltage regulator and the same thing happens. DC voltage starts at 12 slowly increases to 15+ generator stops after about 45 minutes.

It has been trouble free for the 2 years I have owned the boat.

Any ideas would be greatly appreciated.

Paul

[a64pilot]

The generator engine shutting down may well be the low oil pressure switch, they are very often overridden during starting as of course there is no oil pressure then. That is why it will run if you hold the flow plug switch, cause it’s being overridden then.
I would temp install a cheap direct oil pressure gauge to confirm I actually had pressure then once I verified that, then replace the low oil pressure switch.

Now that’s Generic generator and not NL specific, but I bet they do the same as most others.
The high voltage from the alternator, pretty much has to the internal regulator in the alternator itself. Your saying you replaced that?

On edit I assume your alternator has an internal regulator they became common a long time ago, and I doubt the two problems are related

[PJS1554]

It is an external voltage regulator. Just replaced it today hoping the high dc voltage was causing a contact to open. Quite sure it is not doing my battery any good.

I will look into to oil pressure gauge. Something on Amazon?

[a64pilot]

Amazon will be fine, or any auto parts store, your looking for one with the installation kit, which should be several feet of plastic hose and several brass fittings, most come this way.
You can either install a T in the hole the LOP switch screws into, or just replace it with the gauge. Check the LOP switch with a multimeter, with no oil pressure it should show an open, if so then you can connect the two wires together to bypass the switch for the pressure check with a gauge.
I have never seen a LOP switch that was closed with no pressure and open when there was, but I have not seen every one of course.
I do not recommend operating the generator with the switch bypassed as it’s possible it’s working and your losing oil pressure and if that was the case, bypassing it will seize the motor.

However loss of oil pressure is exceedingly rare and LOP switches going bad isn’t all that uncommon.

Keep the oil pressure gauge, you may one day need it to check the engine.
However if you choose to do a permeant install of an oil pressure gauge, I recommend using one with a sending unit as opposed to the plastic tube. The plastic tube or even if you go with copper is too flimsy for me, too likely to one day spring a leak.

[PJS1554]

Thank you very much for the help. I will not be back to the boat till Saturday. I’ll let you know the results.

[GordMay]

Greetings and welcome aboard the CF, Paul.