Hi there,
If I remember correctly this model does not use a fuel/oil mix. Please confirm this.
If what you are saying is that in filling the device with gas and checking the oil level, both overflowed, then we are good.
As you have done, drain both to their proper levels.
Now pull the spark plugs, they are most likely fouled with oil.
Turn the generator over a few times to clear the cylinder of excess oil.
Give the plugs a good cleaning. You may need to replace them. I just have a thing about tossing something with life still left in it.
Put the plugs back in and fire it up.
Best regards
Mike