It's hard to tell by the video what's making the sound, you will likely need to better pinpoint the location of the sound. I also recommend the dowel/broomstick method, just be VERY careful of how close your face gets to moving parts.
sometimes with the motor OFF you can try to spin stuff and see if it feels loose or like it may be grinding or things of that nature.
it is however most likely the generator or water pump.
