High Altitude Diesel Generator Smoking

[Dudley]

My 5kw Onan starts normally at low or high altitudes, but above 6,000 feet it smokes alot after starting for about 15 to 20 minutes. It also runs rough above 8,000 ft. It sounds to me that it may be starving for air, and the air filter is new. Does anyone know of an adjustment for higher altitudes? The Onan dealer had no clue.

[dickandlois]

Your model should have a high altitude setting on the carburetor, just a small lever on the unit that resets the fuel mixture on the engine for operation at elevation. Like over 5000 ft. It is pictured in the Owners Manual.

Remember to reset it when you get back down off the mountain. Might want to have a post it note somewhere to remind you.

Rich.

[wolfe10]

We need to clarify-- is this a diesel or gasoline generator.

Full model number really helps.

[dickandlois]

Good catch Brett ! I did read the 5KW and that is gas size generator. However! the altitude ajustment is not listed for the HCJAA. only HGJAB and HGJAC.

Onan makes a diesel in the 3k range then they go up to the 6 kw size.

Rich.

[Dudley]

The Onan is a 5KW diesel. I forgot to mention that. Model 5.5HDKBA-3590B

Dudley

[dickandlois]

Dudley,

Thanks for the information.

The problem is a combustion issue. Your generator is a newer product, using a 2 cylinder engine and is configured differently from the more common 6K to 8K generator configuration.

You mentioned the air filter has been changed. How many hrs. on the generator?

Have you had any fuel issues with the coach? Water or dirt in the fuel.

Have you run any injector cleaner through the system?

Fowled fuel injector, carbon build up in the exhaust system and any restriction to the air flow through the engine can cause a combustion problem, that is more prevalent at higher altitudes.

The fuel and air filters on you unit are accessed directly under the unit by removing different access covers.

The spark arrestor clean out is in a slightly different location. Look in your Owners Manual for the proper procedure if you are a DIY person.

Rich.

[dave111451]

What color is the smoke ? In general, white is not enough fuel, black is to much, blue is oil smoke.

[Dudley]

The generator has 259 hours. No fuel problems with the coach, and I have not run any injector cleaner through the system.

The smoke is white.

Thanks for the information.

Dudley

[dickandlois]

As Mentioned white smoke is low fuel supply.

The things that come to mind are. Fuel filter, Fuel pump or restriction in the fuel line, this could be do to the fuel line being crimped in some manner or some thing in side the line itself.

Just got to ask if this has happened when you are at altitude in the last few mouths or has been an issue from the day you picked up the coach? Not allot of hrs. on the unit.

Wondering if something like a very small air leak in the fuel line somewhere.

Interesting because it works at lower altitudes with no smoke,, one would think the white smoke would be more prevalent at lower altitudes because of greater air pressure.

Rich.