RRTFD
I have a 2016 Generac 22kw Stan by home generator s/n 3000015083 that the carb surges under load or no load. I have 7.8 inches of water column at inlet to gas valve. Any ideas???
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Peddler
While it is running  try unsnapping the air cleaner cover and lift it a little, see if that smooths it out. 
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78buckshot
We can assume the unit is running on natural gas by the pressure stated. Several things can cause the surging, incorrect gas system, gas regulator vents plugged, regulator/s need adjustment or replacement, kinked rubber fuel hoses, torn seals in the NAT./LP fuel selector pin, plugged or wet air filter, etc. Try the air filter lid as Peddler suggested - it might give us more to go on.
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murphy
The title to the thread says it's running on NG.
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BrianMartin
Make sure there is no obstruction in the air flow in the battery compartment. Most of the time I find replacing the air filter smooths things out.  
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Birken Vogt
This has been a very long standing problem with these models with no real definitive solution.  My observation is that it seems to have something to do with stepper motor step counts getting out of whack.  But that is just a hypothesis based on observation.  "Most" of the time it causes no real problem.
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78buckshot
Sorry Murphy, I didn't see the NG in the title, I'm used to the details in the main text.
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BrentB
RRTFD wrote:
I have a 2016 Generac 22kw Stan by home generator s/n 3000015083 that the carb surges under load or no load. I have 7.8 inches of water column at inlet to gas valve. Any ideas???

Back off to 5" W.C. and see if that smoothes it out.
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bhm_to
My older propane 22Khw generic was doing this last spring. Would also stop under load. After lots of different solutions like gas valves it ended up being the stator motor, an easy 15 minute swap. Has run well ever since. Make sure stator arm is moving freely as it should. 
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78buckshot
bhm-to, I think you meant to say STEPPER motor, just want others to have the info. Thank you for the input.
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MacL
The label on the back of the generator states a fuel pressure range of 3.5"-7" wc.  And you're at 8.  Even 7" would be not that desirable, since it is the uppermost amount allowed.

Excessive fuel pressure will contribute to surging.  Try to set it around 5".  Do not set it below 5" unless you're on a 2# system .

After this, permanently remove the deflector that is behind the battery, and your problem should be solved.  

Unplug and re-route the stepper cable so that it won't dangle and get sucked into the front of the engine whether or not you remove the deflector.  You'll need to wrap the stepper cable around some harnesses to keep it up and out of the way.  Or coil it up and zip tie it up to something.  When plugging the stepper back in, the ridges (wards) on the plug face toward the front of the generator.
State your problem, not your diagnosis.
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