Excessive Smoking on Generator Start-up

[LaserMark4]

I have a 10KV Onan Quietdiesel with about 330 hours on it. Serviced it recently and it runs great.

Only problem is when I don't start it for some time (say over a week), it starts up with a huge cloud of white smoke. Takes 20-30 seconds to fully clear and then runs perfectly clean with no visible emissions.

Anyone have that issue previously? Might it be a ring problem letting oil slip down into the cylinder? Just seems strange to have that issue with such a little used generator.

[LaserMark4]

Might add it happened when it was quite cold- in the 20's and 30's. Would temperature cause this?

[Joe-K]

I've always been under the belief that white smoke is unburned fuel due to the cold engine not completly burning the injected fuel. Since diesel ingites when it is brought up to temperature via compression, a cold engine does not completely burn the fuel charge until it get a little heat built in the engine. Those first few seconds of the cold engine smoking a bit I believe are normal.

Did it just start doing this when the weather turned cold?

[LaserMark4]

Quote:

Originally Posted by Joe-K I've always been under the belief that white smoke is unburned fuel due to the cold engine not completely burning the injected fuel. Since diesel ignites when it is brought up to temperature via compression, a cold engine does not completely burn the fuel charge until it get a little heat built in the engine. Those first few seconds of the cold engine smoking a bit I believe are normal. Did it just start doing this when the weather turned cold?

Come to think of it, yes, on cold mornings which were nearly every morning on the trip (20's and low 30's at Yosemite, Colorado/Utah mountains on the way home, etc.). The smoke has definitely been white.

I'm thinking maybe you nailed it-- cause when we cranked it up later in the days towards evening to recharge again, no smoke to speak of at all.

[Meandering Retiree]

I push the starter button on the bottom for 10 to 15 seconds, the light flashes quickly, and this preheats the air, causing it to start quicker and have less smoke when it does start.

[Poltax]

White smoke on start up generally means that there is unburnt fuel on a diesel. It also means that the cylinders are not warmed up enough to burn the fuel. Remember that a diesel is run on compression and not on a hot spark plug. That is why most all diesels will have some type of heating system on start up, be it glow plugs, or intake/air heater.

[BaldOldBob]

Quote:

Originally Posted by Meandering Retiree I push the starter button on the bottom for 10 to 15 seconds, the light flashes quickly, and this preheats the air, causing it to start quicker and have less smoke when it does start.

I heartily second this. Not that it is necessarily the solution to your problem, but doing this seems to definitely mitigate the smoking problem. After waking up to 4 inches of snow in Moab, Utah yesterday morning, I can assure you it definitely works in cold weather. By the way, Arches National Park was like a winter fairyland with all that snow!

[LaserMark4]

Quote:

Originally Posted by BaldOldBob I heartily second this. Not that it is necessarily the solution to your problem, but doing this seems to definitely mitigate the smoking problem. After waking up to 4 inches of snow in Moab, Utah yesterday morning, I can assure you it definitely works in cold weather. By the way, Arches National Park was like a winter fairyland with all that snow!

Man, I am jealous. I bet that was a once in a lifetime view. That area is really magical, along with Brice and Zion.

I've been holding down the start button (flashing) prior to start but it has only been 2-4 seconds at most before firing. So I will check out if maybe there is something not operating correctly in that circuit that is not allowing the pre-heating mechanism to fully operate prior to firing up.

Thanks for all the good advice friends.

[WW]

You might check the air filter on the generator. Had the same problem once, hated to start the generator because of all the smoke. Changed the filter and problem solved.

Chester

2006 Monterey