Troubleshooting generators generator starts and runs fine for approx. 15 minutes ,starts sputtering an shuts down?

Have you stripped and cleaned out carburettor?
sounds like a blocked idle jet?

You might have a thermal issue with the ignition coil shutting down after it gets warm. Happens.

Make sure the gas is fresh. Also, take off the carb bowl and look for signs of gumming. If there is gooey stuff in the bowl, then the carb needs to be cleaned.

Clean the air filter. My mower always tells me when it needs it by doing the same.

Do you have an air filter on that thing? Sounds like it's straving for air.

This sounds like overheating. These small generators don't have overheating protection, but if a low oil pressure or low oil level is present it may be the reason for stopping.

Check the oil level in the starting conditions and again when it stops. It may become under the "stop" level and after some time the precipitated oil has reached the "start" level. The same may be with oil viscosity and oil pressure.

Try to add some oil or change the oil with bigger viscosity.

I would venture a guess that the heating element has become intermittent with a short. Wasn't so bad before, but played heck with controller due to noise from arcing, but now have a dead short when heater reaches temperature.

you dont say if diesel / petrol.
if petrol check the choke mechanisim.
if diesel injector may need cleaning or re setting

Check the oil pressure switch



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It sounds like you are not getting enough gas. I think it's the diaphragm, When you take it off of the choke diaphragm controls the gas flow, apparently yours is just shutting down. It's very inexpensive, and very easy to replace. Good Luck :)