Help! Onan 4K generator refuses to start and stay on

When u check the Onan 4000 oil level is the oil up to the full mark on the dipstick ? If so it might be over full.
I always pre-measure the amt of new oil that add during an oil change , then note it on the dipstick as my full mark.

There is a video of an Onan faulty dipstick where the full mark should read 1/2 way between full and add lines. As per the video, this has been resulting in your symptoms of starting, blue smoke then stopping.