Diagnosing Generator Problem

[Renee Schramm]

Our generator has started acting up. Has run fine over the past year we've had the boat. Last week it began acting like it had a fuel problem. It would just shut down, like it had run out of fuel. This happens after a varied run time, never a pattern; it might be after 20 minutes or 3 hours, and with different loads.

Chris has completed the more obvious checks -- changed primary and secondary fuel filters, checked belts for tension, removed water from fuel separator, checked oil / oil pressure, confirmed water flow.

The generator is a 16kw Northern Lights, Model #M-844.

Any other thoughts?

Thanks.

[ramblinrod]

Originally Posted by Renee Schramm

Our generator has started acting up. Has run fine over the past year we've had the boat. Last week it began acting like it had a fuel problem. It would just shut down, like it had run out of fuel. This happens after a varied run time, never a pattern; it might be after 20 minutes or 3 hours, and with different loads.

Chris has completed the more obvious checks -- changed primary and secondary fuel filters, checked belts for tension, removed water from fuel separator, checked oil / oil pressure, confirmed water flow.

The generator is a 16kw Northern Lights, Model #M-844.

Any other thoughts?

Thanks.

Assuming it is diesel, to run continuously, it must have...

1. Clean adequate volume of air.*
2. Clean adequate supply of fuel.*
3. Adequate fuel pressure.*
4. Clean injectors.
5. Proper injector timing.
6. Adequate compression.
7. Proper exhaust back pressure.
8. No auto shutdown intermittently engaging.*

For unpredictable intermittent shutdown, I recommend looking at the items with asterisk first.

What changed since it last worked properly?

If there was any regular maintenance performed, and performance changed immediately or shortly after, look at that first.

If the former my first guess is air in the fuel system.

If it was just time, could be the fuel has turned or become contaminated.

To eliminate that, bypass the water separator and feed the engine a known good supply of fuel (fresh diesel in clean jerry can).

If it runs properly, you know you have a fuel system issue (most likely).

If it still shuts down, then you have to start eliminating the other possibilities.

Contact Northern Lights to get their advice.