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Generator needs more air?

May 28, 2023, 02:57:33 pm

In the Colorado mountains at 10,000', temperature 34 degrees. Generator not liking it. Rough idle upon start up, lots & lots of smoke (gray/blue). Assuming it's the air/fuel mixture. How do I adjust the air/fuel mixture so it gets more oxygen at this elevation? Picture shows the only adjustment I can find. PowerTech 10k genny in a '98 U295.

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Re: Generator needs more air?

Reply #1 – May 28, 2023, 03:04:17 pm

No turbo, no way to get more O2.  Did you let it warm up?  White smoke is unburned fuel.  Not hot enough yet most likely.

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Re: Generator needs more air?

Reply #2 – May 28, 2023, 03:18:52 pm

Yup, no reasonable "mixture adjustment" on that engine.

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Reply #3 – May 28, 2023, 04:04:48 pm

Just wondering, how is your air filter?

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Re: Generator needs more air?

Reply #4 – May 28, 2023, 04:43:21 pm

That is just the governor setting. If the smoke is just after startup I would check and see is all your
glow plugs are working. Also I go with John and check the air filter.

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Reply #5 – May 28, 2023, 09:41:13 pm

Dan, definitely check for other possible issues. I live at 9000' in the Colorado mountains and have never had any issue with the generator not having enough air.

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Re: Generator needs more air?

Reply #6 – May 29, 2023, 08:32:54 am

Before you start it try this:  push start, wait about 7 seconds then push stop, repeat 4 or 5 times then start it. This preheats the engine more than just starting it. It still may smoke some but should smooth out after a few minutes, especially once you add a load to speed it up.
I used this method when we had our lot at 9400'. But if you think the generator smokes try running your aquahot at that altitude!

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Re: Generator needs more air?

Reply #7 – May 29, 2023, 09:04:24 am

Try using some Diesel Kleen in the fuel,it won't hurt,correct me if I'm wrong but I thought black smoke was unburned fuel and
white could be oil.

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Reply #8 – May 29, 2023, 10:40:15 am

My experience is black exhaust is too much fuel burning and white smoke is too much fuel unburned.

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Reply #9 – May 29, 2023, 10:50:45 am

And to help complete the color spectrum, oil burn would be BLUE.

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Reply #10 – May 29, 2023, 11:24:32 am

Re. the air filter, it doesn't "look" dirty but I ordered another anyway and will install it Tuesday when it arrives.
We are 3 weeks and 4,000 miles into our annual coast-to-coast and back trip, and the generator has had no issues up until now. Last week we were boondocking at 6,000' in the eastern Sierra's and the genny ran fine. At the moment we are at a high-end very expensive RV resort where I can't run/test the genny when it's smoking this much. We're moving later today to something more rural and I'll be able to try these suggestions.

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Re: Generator needs more air?

Reply #11 – May 29, 2023, 11:26:23 am

Ours does the same thing at cold temps and high elevation. Once it's running, it puts out a foul smell and a light haze. You need to increase the cetane rating number of the fuel with an additive. Summer diesel will have a lower cetane rating so use an additive. Cetane rating maximum number is 100 with most diesel around 50. Biodiesel from plants is slightly higher with animal biodiesel up to 60. A full tank of diesel will need quite a bit of additive. On our older Mercedes diesel, the factory recommends up to 25% gasoline in freezing weather to keep the diesel from gelling and to give a better spray pattern from the injectors.

A diesel engine with a bad glow plug will be harder to start (or may not start) especially when high altitude and low temps are encountered. Low compression also won't help. Glow plugs are easy to check and an additive may not only raise the cetane rating of the fuel but may clean the injectors so the spray pattern has more small particles rather than the solid streams from dirty injectors.

The air cleaner won't do much as the air needed to start the generator is very low. When the air cleaner is clogged, the generator (or main engine) output may be less and EGTs higher at high loads. If you don't believe me and have a side compartment generator, just pull the air cleaner off as it only takes a minute and then check how it starts at high altitude and cold weather.

At Yellowstone in 17 degree temps and 8000 feet., it took about 10 minutes to get the generator started and I melted the Detroit battery terminals and had to use vice grips and lots of ether to get the main engine started. This was dry camping (no juice).

A generator with a turbo, once started, will run nicely and smoke free at altitude but may be harder to start as some turbo diesels will have lower compression pistons, like our Detroit 6V-92TA in Foretravels. At 19/1 compression ratio, my 8V-71 was instant start in almost any weather while our U300 diesel with 16/1 is more reluctant in cold weather. Detroit generators were sold with the compression ratio configured for the altitude of the user if in a fixed location.

Pierce

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Reply #12 – June 07, 2023, 07:44:37 pm

Okay, I finally made it back down out of the mountains today and started the generator up again. Not a puff of smoke. Smoke was so thick and stunk so bad last week at 10,000' it made the genny unusable. I suppose I could have let it run longer to warm up and put it under a load as some folks suggested, but I didn't get to try that in the public campground I was at. Anyway it's good to see that it runs and performs fine again at lower elevation.

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