Smoking Generator

[Kwajdiver]

My Power Tech gen, after running for three hours, started pouring black smoke out of the exhaust.  It smells a little hot. The water and oil have been checked and are okay.

 I noticed the lights dim when I started the mircowave.  Already running were inside lights, two overhead heaters, one space heater, one TV.

Now I don't think I should be running it overnight.  Of course there goes my heat........

Bill
Little Rock,AR

[Len Silva]

Have you checked the air filter?

Len

[Kwajdiver]

NO I haven't, good place to start.....

Thanks,

[pvcces]

Black smoke and dim lights could be from overloading, too. I guess that's going to depend on just how large the generator is.

Tom Caffrey

[TomC]

Give us a clue what size the gen is.  You can take out the air cleaner element and try running it under the same circumstances to see if it still smokes-it won't hurt it to run a few minutes without the air cleaner element.  I do recommend you just pull out the element and then put the air cleaner assembly back together so no big chunks get in.  Most likely-that's it.  How many hours on the gen?  What altitude are you at? What is the wattage load you are putting on the gen?  Good Luck, TomC

[JackConrad]

Looks like he is in Little rock, AR. City-Data.com says the elevation is 335'.  As was already mentioned, it would help if we knew KW rating and total hours on generator as well as total load applied to generator at the time this occurred. 2 roof heat strips plus a floor heater plus lights plus a microwave could be a considerable load.   Jack

[Kwajdiver]

The Gen has 2000 hrs. and it's 8000 watts, (I think) this could be very wrong.  It came under load when I kicked in the Microwave.

I had to make a quick car trip to Beaumont, Texas. Should be back at the bus Thursday morning.  Had to put the bus in the shop for a couple little things.  Had them change the fuel filter also.

Wouldn't loading down the gen, just blow a breaker?  Would it make it smoke, like a fogger?

Thanks for the input,

Bill

[TomC]

You would blow a breaker if you over load it electrically.  At sea level, most generators will have enough reserve power where it should maintain rpm even at over load and the breakers would blow.  If you are over loading the engine because of a malfunction in the engine, then you'll get lots of smoke.  Dirty air cleaner comes to mind, also a broken injector tip?  Good Luck, TomC

[Hartley]

Only a guestimate but if you already had a 5,000 watt load on the generator
and you dumped another 1,100 watts on it from the microwave you probably
were getting close enough to max horsepower load on the engine for an 8kw
generator. What you didn't mention was whether there were unseen loads
already present such as an Inverter/Charger and Water heater.

Many times if you approach the 70% load factor these little engines will start to send black smoke
if the demand is loading more than normal.

My Onan 10kw will do that when I run both roof airs, water heater and forget to reduce the
load share on the inverter when its in full charge mode pulling 20 amps. Of course mine is getting old
and has probably 4,000 hours of abuse on it now. It's a 92 model with a kubota 4-cyl and was rode hard
long before I got it and I haven't been kind to it.

One other thing that might do some fogging is if the generator engine is running a bit on the cool
side ( stuck thermostat ) the unburned fuel situation can occur and the engine will load up. But worn
injectors could also cause that...

Dunno, Just guessing, Hope it's something simple...

[TomC]

Dr. Dave- 4000hrs is nothing for these gensets.  I've heard of 31,000hrs, had a friend that sold a 8kw Powertech with 23,000 hrs still running with full load capability.  If yours is feeling tired, maybe time for a valve adjust.  Good Luck, TomC

[Len Silva]

I think that there is also the possibility that the generator ran for a time very lighly loaded.  It might smoke a while when a full load is applied.

Len

[DrivingMissLazy]

Unfortunately, based on the information provided, I am going to guess an engine failure of some kind. None of the other guesses make sense to me. Please let us know what you find.
Richard

[Kwajdiver]

Thanks for all the input.  I'm back in Little Rock and back in the bus.  It will be the weekend before I have time to give it a load test.

Air and fuel filters are new or clean. I did run it for 45 minutes today, with NO LOAD.  Seem to run fine. This weekend I will run it for 30 minutes then start appling a load, will keep stepping up the load to see if the problem returns.

Thanks Again,

Bill
Still in Little Rock, AR

[Busted]

99 percent there is nothing wrong with your gen. The heavy load, especially the heaters, will clean that Kubota out. If the air filter is not free and clear with a big load, expect to see healthy black smoke, and probably some carbon coming loose in the form of pretty glowing embers. The power factor of your Powertech is 7.5 PEAK at 100 percent. Don't expect 7500 cont. It might do it, but it won't be pretty.
Good Luck

[Kwajdiver]

Okay testing is complete.......  I put a current probe on my shore power, turn two over head A/C units on heat. One 1500 space heater, TV, water heater, switch the frig to gas, turned on the lights, set the Mircowave for one minute.    I pulled 50.6 amps.

The Gen, Power Tech 8KW, 66 amps, has a new fuel filter, and cleaned, (not new) air filter.  Had been running for one hour, with NO Load and no problem.  Switched over from shore to gen power.  Slowly brough up power items to the same 50 amps, as on shore power.  Let it fun for 10 minutes, no smoke, no problem.

Looks like whatever caused me the problem is no longer.

Do have a question.  The gen is in my second bay.  There is a hole, 12x12inches, cut in the floor under the gen.  Guessing the gen needs air to breath.  This hole sucks up a lot of dust and dirt.  Is the hole needed?  Should I put some type of filter over it?

Thanks for the input....

Bill
Still in Little Rock, AR