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Generac runs rich

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hbockoven
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2016/07/29 16:32:50 (permalink)
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Generac runs rich

My Generac GP6500 doesn't sound right. It seems "bogging", does not get to/maintain 3600RPM at no load idle. Turning off the fuel and letting it run dry, it smooths up and gets to correct RPM before running dry. I have opened and cleaned the carb, jets, float and needle valve. Still the same problem. The generator runs fine on LP. The generator was running fine on gas and the LP kit and this is a new issue. It has a Huayi carb, but I can not find any fuel/air adjustments.

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    Mikel1
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    Re: Generac runs rich 2016/07/30 15:35:37 (permalink)
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    Try running temporarily without air filter, any change? Choke plate fully opening?
    hbockoven
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    Re: Generac runs rich 2016/07/30 16:16:42 (permalink)
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    Yes, it does run better without the filters. I washed and dried them while cleaning the carb. Still runs like it is bogging and lacks power. Choke full opened after starting. It does sound like it misses and the exhaust gas is HOT no load. It will light a cigarette where it exits the muffler. I don't recall it ever being that hot.
    New gaped plug. Inline spark tester shows bright and steady, even when it sounds like a miss.
    I checked valve clearance. Maybe a valve job?
    This generator has NEVER seen gas/alcohol blend fuel. Only the good stuff and is exercised weekly.
    There is a Generac repair place 20 miles away. I think I will take it in. It does get used frequently where I live. 
    Mikel1
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    Re: Generac runs rich 2016/07/31 21:10:55 (permalink)
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    That is interesting, will it accept a load on it? Any popping at exhaust?
    If you do decide to take it to Generac. Let us know what the problem was.
    hbockoven
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    Re: Generac runs rich 2016/08/01 18:08:10 (permalink)
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    Mikel1
    That is interesting, will it accept a load on it? Any popping at exhaust?
    If you do decide to take it to Generac. Let us know what the problem was.

    It will run with a decent load, just sounds like crap and doesn't get up to RPM. Noticeable flickering of lights. I wouldn't call it popping. I hear a difference at times when it is trying to get to RPM. When I changed plugs, the old one was black (no crust) and wet. It isn't mixing fuel/air right it seems...being on the rich side. It starts easily.  The carb doesn't seem adjustable. I will have to see what the repair center tells me.
    Mikel1
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    Re: Generac runs rich 2016/08/01 23:08:24 (permalink)
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    Yep, black and wet on plug, washing the cylinder.
    Might try cleaning carb in ultrasonic cleaner.
    Might be cheaper to just replace carb, seen some on Amazon & eBay.
    hbockoven
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    Re: Generac runs rich 2016/08/02 17:31:07 (permalink)
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    Mikel1
    Yep, black and wet on plug, washing the cylinder.
    Might try cleaning carb in ultrasonic cleaner.
    Might be cheaper to just replace carb, seen some on Amazon & eBay.

    I asked my local small engine repair place, not a Generac facility, about it. He said those Jap/China carbs are mostly replace only and it would probably be cheaper to just buy and replace the carb myself. Looks about a $60 part. Mine does not have a bowl solenoid and one from sears on-line says it is a direct fit. No solenoid on it but does have a dump fuel port...that mine is lacking.
    I will remove it and soak it in parts cleaner for a day or so before ordering. Maybe I will get lucky.
    Mikel1
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    Re: Generac runs rich 2016/08/02 23:15:26 (permalink)
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    I agree with your small engine shop. However I can understand someone trying to clean their carb, worth a try at least.
    Best of luck😀
    hbockoven
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    Re: Generac runs rich 2016/08/06 21:54:19 (permalink)
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    I think I got it. I took it apart again. I didn't know there was a valve/port under the plastic piece next to the plastic screw last time I tried to clean it. Removed that, soaked everything in cleaner, and blew barb cleaner through everything till the can was empty. It runs much better and I was able to adjust it to hold at 3600RPM no load...or close as my tach is a cheap china add on that bounces around a little.
    Do you have any idea of parts that commonly fail on Generacs? Since this does get some 70+% load use, I wonder if having spares handy in case of a failure during a long term grid down situation would be a good idea.
    Mikel1
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    Re: Generac runs rich 2016/08/09 22:36:39 (permalink)
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    I may not be the best person to answer your question. I live in Georgia, I never needed a generator till an ice storm in '14. Bought one after that. Most of the people that had generators had a hard time getting them to start. Majority of those were from old fuel gumming up the carb.
    hbockoven
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    Re: Generac runs rich 2016/08/10 14:18:40 (permalink)
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    Thanks for your help! I always turn off the fuel and let the genset run dry so the carb is empty. But the fuel in the tank, even with stabilizer, is a possible issue.  I drain it yearly even though it gets used and filled a few times...but still. Another reason for the LP/NG conversion. I think I will get a spare carb since it is not that expensive. Well worth the money compared to sitting in the dark with a non-working generator and sump pump. Been there, done that!
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