8kw Onan diesel quiet generator

Well after running the engine and generator during the winter, and our last 4 hour round trip, the fuel tank was down a third. So today I went and topped it off again, about 30 gallons.

Started the generator again and turned on both air conditioners. We then took it for a 45 minute ride on the freeway and back to the storage yard. MH ran great, the air conditioners worked fine.

So after parking with the gen still running and air on I went out a took another look. No smoke or smell. Everything seemed ok. So maybe the fresh fuel worked, or just needed to run more, or there was a little water?

But thanks for the help, I'll be keeping a eye on it.

After verifying that you don't have coolant in the oil and/or smell it in the exhaust and that the oil is just that-- oil and not diluted with fuel or showing coolant: Run it for an hour under high load-- perhaps both A/C's and block heater.

It could just be that all the light load running this winter needs to be cleaned out. Could even free up a carboned injector tip.

Diesels don't like to be run at light loads, particularly in cold conditions. That goes for main engine as well as generator. You will find Onan (and other generator manufacturers as well) recommend loading the generator to at least 50% of capacity when running it for exercise.

If there was water in the fuel I would expect that you pulled it out on your trip. If you are getting coolant into the combustion chamber then you generally get combustion products into the coolant. Check for oil film on the coolant or just soot. Sometimes you get blowby out the coolant fill. If all that checks out fine I would try to get fresh fuel in there and see if the problem goes away. I hope that it does.

I find it interesting that your exhaust residue does not seem to match the smoke color. Oil in the exhaust indicates incomplete combustion or oil entering the exhaust after combustion. I don't know how oil would enter the exhuast without a turbo charger. My first suspicion would be fuel quality but that should affect your main engine as well. Does it show any of these symptoms? If the problem does not go away real soon you need to get Cummins involved.

Groover wrote:
White smoke in the exhaust is often associated with water. Keep an eye on your coolant level just in case and your fuel quality. It sounds like you let the coach sit since last fall when you added the fuel stabililzer and biocide. You may have condensation in the fuel. That would not be good at all. Did you store it with the fuel tank full? The less air there is in the tank the less condensation you will get. Also, it is recommended that you run the generator monthly for 2 hours at a time under load. Have you been doing that and running the main engine as well? Is there water in you main engine's water separator?

The tank was topped off when put into storage. I ran it one hour every other week and turned on the block heater for the load.

It ran rough during the extremely cold weather when first starting each time in the winter until warmed up. I did notice a small cloud of white smoke each time when starting cold during the winter. Didn't notice that yesterday when it started.

We used the MH two weeks ago on a trip. It ran fine as usual. Didn't notice any degradation in power or engine performance. I will have to look at the water separator.

I have noticed the inside of the gen exhaust has black oily residue like soot

White smoke in the exhaust is often associated with water. Keep an eye on your coolant level just in case and your fuel quality. It sounds like you let the coach sit since last fall when you added the fuel stabililzer and biocide. You may have condensation in the fuel. That would not be good at all. Did you store it with the fuel tank full? The less air there is in the tank the less condensation you will get. Also, it is recommended that you run the generator monthly for 2 hours at a time under load. Have you been doing that and running the main engine as well? Is there water in you main engine's water separator?

WILDEBILL wrote:
Could be, how many hours on the generator? Have you done the annual oil and filter change including fuele? By the way there isn't a choke on your Quiet diesel.
Bill

Yes had the maintenance done in the fall before storage. Around 60 hours. It was ran to keep the batteries up during the winter. I just noticed this today because of the smell.

Could be, how many hours on the generator? Have you done the annual oil and filter change including fuele? By the way there isn't a choke on your Quiet diesel.
Bill