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Smoke from Gen

Discussion in 'Generators/Gensets' started by jmatson, May 4, 2016.

  1. jmatson

    jmatson Member

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    I just got a 100 kw Gen, Running a Deere 6068T engine. It smokes like no other. It looks white but it doesn't smell like unburned fuel. I found couple leaking fuel connections i fixed those. Any suggestions would be great other than taking it in for service.
     

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  2. GregsHD

    GregsHD Senior Member

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    Do you have any way to put a heavy load on the genny? Possible it's been sitting for a long period or ran with light loads? It should clean up after loaded for a while, if this is the case. Is the engine oil overfull or diluted?? Does it have much blowby? Have you changed fuel filters? If it had fuel in it when you bought it who knows what could be in there?
     
  3. fast_st

    fast_st Senior Member

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    How many hours on it and how much blowby. Could be passing some oil from the turbo, give your inlet pipe an inspection sometime.
     
  4. jmatson

    jmatson Member

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    it has apx 17k hours.

    No clue on blow by.. I have a friend coming to look at it Friday..

    Oil was changed 2 months ago.. It's still thick no trace of fuel. I used it today to power my concession trailer about 100 amps at max. It didn't' smoke as much, as no load. As in the fuel no clue how long that's been in it.. This was used as a rental and it was smoking when they had it and did very little diag. They think it's just injectors.
     
  5. Nige

    Nige Senior Member

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    That photo looks like the classic case of a genset having been run for long periods at very low or no load. Before laying a wrench on it get it connected to a resistor load bank that can take at least 50% of the genset output and preferably somewhere around 80/90%. Run it for a couple of hours at as much load as it will stand and then check the smoke from the exhaust again. You may find that's all it needs, and even if not piston rings/liner condition is likely to be the root cause of the smoke, not injectors.
     
  6. jmatson

    jmatson Member

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    ok, Im taking it to my paintball field today.. Going to run my compressor.. IT was loaded tested april last year and same result happened sdf.jpg
     
  7. Nige

    Nige Senior Member

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    Thanks for telling us that after you asked for opinions ........ nothing like getting the full story in bits & bobs. Is there anything else we should know..?
     
  8. jmatson

    jmatson Member

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    I just got that email in the day i posted it. .When i got it i was told nothing other than it smoked little.
     
  9. jmatson

    jmatson Member

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    ok thanks.. I will try that i used it this weekend. But max amps i was pulling is 83 amps and of course It wouldn't smoke under a load. But when my fryer kicked off it went back to smoking.. I ran my scuba compressor on it. 3 phase 40 amps, It ran great no smoke.. Until it was done filling up.. BUt that was the first time i ever ran the Elec side of that compressor and was much much faster than the Diesel side.
     
  10. Nige

    Nige Senior Member

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    To test for a bad injector have you tried cutting out the injectors one at a time and running the engine at no load to see if the smoke clears..? I know it will run like a bag of bolts with one cylinder off but all you are trying to achieve is to see if the smoke clears, not run it for an extended period.
     
  11. jmatson

    jmatson Member

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    I had all 6 injectors replaced. And it's still blowing smoke. I'll have it back home on Monday. And going to do a compression test on it. I know I said it smokes at idle. But it really doesn't idle it runs st 1800 rpms no load or loaded.
     
  12. fast_st

    fast_st Senior Member

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    Would it be pretty easy to pull off the intake and exhaust manifold and look for oil pushing past the valve guides? I'd imagine valve guide leaks would reduce quickly under boost/load Nige's suggestion is a good one, our genset had a variable exciter and the mfg said, once a year, short the bus bar, excite to 0 and warm the engine up, increase excite until 90% amperage is reached, run for 1 hour

    It was an old old generator but doing that seemed to make it start a lot easier.
     
  13. Nige

    Nige Senior Member

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    Sometimes if a genset has been run for long enough on a low or no load the piston rings end up being baked into the grooves with carbon and nothing but a stripdown and clean along with new piston rings will fix them.
     
  14. fast_st

    fast_st Senior Member

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    So if the rings were stuck, would an oil sample show high fuel? or would it just show up as high oil consumption?
     
  15. Nige

    Nige Senior Member

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    On a Cat engine it would most likely show up as high soot due to the blow by, because the engine isn't burning any more fuel than normal. On this particular engine I honestly don't know.
     
  16. old-iron-habit

    old-iron-habit Senior Member

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    I think you need to run it under full load for a extended time frame. A few minutes under load will not clean it up. All hospital generators in the USA which are typically run for 30 minutes once a week are now required to run a 4 hour load bank session every three years. History has shown many times that when needed they were not performing due to crapped up from running with out enough load. I've seen your issue dozens of times. But then again you do have 17,000 hours so who knows.
     
  17. lantraxco

    lantraxco Senior Member

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    That also shows up deficiencies due to age. As told to me by the CAT tech: Had a hospital in Portland with some three or four year old CAT gens, power went out in a storm, so both generators auto start, sync and transfer the load. Both engines running normally, all green, so #2 shuts down and waits faithfully. #1 carries the load handily for fifteen or twenty minutes, senses an overheat. Number 2 fires back up, syncs, takes over the load and #1 shuts down. You can see this coming right? Short time later #2 overheats and there's nobody left to turn to. Now we're down to battery lights and OR's where they're bagging patients by hand to keep them breathing. Not happy. The external coolant heaters were plumbed in with some nice coolant hose that rotted but looked okay, and of course both were installed at the same time with the same hose. Extended runs under load show up some of these unexpected issues.
     
  18. jmatson

    jmatson Member

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    Ok. just a update.. It's at John Deere, There is ALOT of carbon build up on the exhaust ports. Had the head pulled off the cylinders look great you can still see the marks, There is some carbon build up on the piston tops and at the top of the cylinder, Im sending the head out to be checked. There also was no thermostat in it. Would also explain the carbon build up Since the engine isn't building any heat.
     
  19. fast_st

    fast_st Senior Member

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    well that sounds horrible! no thermostat, poor beast.
     
  20. Nige

    Nige Senior Member

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    The carbon IMHO is a classic symptom of running for long periods with no/low load, the lack of adequate coolant temperature due to the missing thermostat has just added to the problem.
     
    Last edited: May 25, 2016