My Coleman Powermate 7000 won't start. Ran for 15 minutes turned off. Tried to start again, but won't start. Drained old fuel, refueled, checked oil, changed spark plug, sprayed carb with carb cleaner, still won't start. Used once and sat over the summer. Help, frustrated.

I not you said you "checked the oil level" My experience with most portable generators is that they must me positioned as level as possible and the oil level must be fully serviced as full as you can get it without oil leaking back out of the dip-stick hole on units WITHOUT an extended dip-stick. Unless those conditions are met the low oil level sensor ends up presenting a false low oil signal and it grounds out the ignition. DO you have Spark at all? If you do have spark and it still does not run respond with the MODEL number off of your ENGINE and I will show you where the main fuel jets are located so you can make sure the orifice is clean.
Some units have a fuel solenoid that presses into the main fuel jet recessed area and shut off the fuel to the carb. This is also an area that debris causes havoc.

Thanks,
Kelly