Brand new Predator generator runs for 20 minutes then stops
I just bought a brand new Predator 420cc 8750 Max/7000 Rated Watts from Harbor Freight. I put 5W-30 oil into it up to the fill line and put 5 gallons of 91 octane fuel into it. It starts up just fine with the pull cord (I didn't want to shell out the money for a battery for the electric starter) and runs for 20 minutes just fine. After 20 minutes it will just shut off abruptly. I have tried running it with no load (nothing plugged in) and also with load as I was thinking that maybe it had an auto-shutoff feature if it detected no load. That wasn't the case. I also checked the manual and it only has a low oil shutoff feature. I don't think it is low oil, as I just filled it up. I checked the throttle and adjusted a screw that seems to control how low the throttle can go, but that didn't seem to do anything to help. I don't know much about engines, so I would appreciate any help.