Generator No start, please help

Sounds like it possibly what the other gentlemen said with to much choke. But, also could be spark timing. I am a small engine mechanic and although i am not familiar with this specific type of generator it sounds like to me if its popping back through the carburetor it could be timing. I have seen several times where the key shears off at the flywheel and causes the engine to become out of time. Something like this makes sense because it just happened after running fine. It could also be a valve issue. If it pulls over easier than usual and or binds up when you are pulling it over; try pulling off the valve cover off and pull engine over slowly and observe the push rods(. I am assuming its over head valve as most of them are). Each valve should go smoothly through its cycle. 2 different scenario's hope it helps!