Northern Lights Genny shuts down

[jimellifritt]

Looking for help with 6KW M673L3.

The genny will run for approximately 20 minutes than shots down. It will restart but only if I hold down the bypass. I do not have the gauges, but with a lazer temp gun it is 165 degrees. I have tried replacing temp sender with new one, no change. The genny has 75 hours on it. I am assuming the oil pressure is good as the engine will run for 20 minutes. If I wait for an hour and the genny has cooked down a bit, it will start and run once it gets up to165 it shuts down. As a side note I tried starting genny after the engine room was hot from a 4 day transit and it would not start unless the bypass was held down.
Any thoughts?
I am trying to buy the gage set now to see what true temp and oil pressure is.
THX
JIM

[IRENE]

The preheat need to be pressed/energized until the generator starts, regardless of temperature.

Perhaps it is getting hot at the mixing elbow, and the sensor there is shutting it down. Troubleshooting would include taking the temperature there with your IR temperature gauge as it heats up and shuts off, verifying this is the issue.

Check for unrestricted raw water flow from the outside of the through-hull to the water pump">raw water pump. Check the the condition of the impeller, it is an annual replacement item. If it comes out I would install a new one vs. reusing. Drain coolant, then remove and clean the heat exchanger. If there are bits missing from the impeller, you will probably find them in the heat exchanger. The small clamp on the rubber boots (both sides) over the heat exchanger get tightened before the big clamps. Flush with a gallon of distilled water. Refill with proper coolant per manual. All of this can be done in a couple of hours.

If you have not inspected and cleaned the mixing elbow, now is a good time for this. Under loading can permit carbon to build up inside. A stainless replacement is an improvement as the cast original will eventually fail. I’m not sure if this would contribute to your problem, but it is a simple maintenance item to address.

[Eder]

My NL gen has done this before...impeller was toast.

[Chotu]

This is certainly a cooling system problem. It is an overheat shut down almost 100% for sure. You’ll have to go through the cooling system a bit. Impeller, clean out the heat exchanger. It’s not too hard to do. Those big hose clamps make it a piece of cake to take these things apart and put them back together again.

Also, don’t forget to start with the basics. Make sure your through hull is clear and providing enough cooling water. And check that the water coming out the discharge is plentiful.

[GordMay]

“TOP 10 GENERATOR MAINTENANCE TIPS & TRICKS” ~ Northern Lights
➥ https://www.northern-lights.com/news...r-tips-tracks/

NL Operator’s Manual[Troubleshooting Guide starts on pg. 28]
➥ https://www.northern-lights.com/wp-c...05/OM673L3.pdf