Onan diesel generator engine smokes BAD..

[Swannee]

My Onan generator in my Endura smokes severely. It's a Diesel generator. Smokes with or without the air filter gets plenty of air. My rasoning for checking air filter first was the smoke is grey/white and wreaks of diesel. Air does'nt appear to be the problem. Full tank, worked fine days earlier. SO
Is there a fuel/pressure regulator I don't see, could the fuel filter cause the problem? Only thing that has not been replaced is the fuel filter. Any thoughts are appreciated.

[Techie]

You could also check the fuel line to make sure that it is not cracked anywhere back to the tank and sucking up air.