Newish Northern Lights generator leaking oil

[Gdsramos]

Hello. I have an M673L3 6 KW Northern Lights generator (3 years old with 350 hours). After 3 hours of operation, there is a thin film of oil that appears on the floor of the soundproof case. I've cleaned it a couple of times, but it keeps appearing after operation. I have checked all the obvious places (lines, oil filter, made sure it was not spilling from oil changes), and I cannot find the source of the leak.

I would very much appreciate any ideas to troubleshoot this myself before I call in a mechanic.

Thanks

[skipperpete]

You have my favourite small generator and there are a couple of things you should check before getting a mechanic. Crankcase pressure could be an issue if you run the genset very lightly loaded, just unscrew the oil filler cap on the valve cover, hold it tightly and lift it just a little, if it has blow by you’ll see it immediately if its bad, all engines make some amount of crankcase pressure but a pcv valve or a pipe from the valve cover to the intake manifold manages the problem nicely, the 673 has an internal drilling across to the intake under the valve cover so maybe thats blocked. Theres a chance that if the pressure is high it could be making the front or rear crankshaft oil seal to leak.
It might be useful to check the air filter, and if you haven’t had the valves adjusted since the first service it might be worth checking the clearances. Is this film of oil definitely lube oil or could it be diesel fuel?

[Gdsramos]

Thank you Skipperpete for your suggestion. I spent some time with an endoscope under the engine and finally saw that the leak is coming from what I believe is the oil pump (in a casting between the lower Lube Oil Fill and the seawater pump). I don't know if it is an oil pressure problem or a faulty gasket. As you suggested (and I understood), I loosened the top lube oil cap, holding it tight and releasing it, then putting my palm over it, and I'm confident that it is neither pulling nor pushing air (Did I do it correctly). So, I'm inclining towards a simple gasket issue. Thank you

[skipperpete]

The oil pump on the 673 is completely under the timing cover, I can’t think of a way for it to leak other than a cracked timing cover, but its possible that the oil feed line to the rocker gear is loose, its a thin tube with a banjo bolt on each end. Give the oil filer a quick check for tightness , and the oil pressure regulating valve is another possible contender too.

[GordMay]

Pete has you covered.


FWIW:
PARTS MANUAL P673-2
For Models: M673L2, M673L3, M673L3G, M673LD2, M673LD3, M673LD3G, NL673L2, and NL673L3
➥ https://www.northern-lights.com/wp-c.../03/P673-2.pdf

Operators Manual OM673L3 ➥ https://www.northern-lights.com/medi...fs/OM673L3.pdf

[Gdsramos]

Skipper and Gord - Thanks for the help. I am uploading an image with an arrow pointing where I found the leaking gasket. If that is not the oil pump, should I be concerned about the oil pressure? Oil pressure gauge is reading normal during operation.

https://photos.app.goo.gl/XdFQqt4zGn1bX96HA

[kapnd]

Be careful not to overfill the oil sump. This can make a mess in a hurry!
Remember that it is not imperative to fill the oil to the high mark on the dipstick, and maintain the level at that point.
I’d drain all the oil out and refill with the quantity suggested by the manufacturer, note the level on the dipstick, and use that as your new full mark.

[skipperpete]

Hard to tell from the photo, its under the water pump">raw water pump mounting flange, AND the base of the oil filler, AND, not too far from the front crankshaft oil seal. It could be as easy as a leaking fill cap seal or a loose bolt or as hard as a crankshaft seal, if there’s no crankcase pressure its hard to explain why there’s a leak albeit a tiny one.
I missed mentioning the oil change hose, check the cap for tightness and closely onspect the oil pan connection.

[Gdsramos]

It is directly under that square casting between the water pump and the lower oil cap. I can see it seeping out under there. I was able to tighten the bolts that hold the water pump to this casting a bit, but it made little or no difference. I also checked the oil hose and all is okay. I will procure the gaskets for this flange and hope for the best. I appreciate your help skipperpete!