Generator runs 30 minutes, shuts off

[Romer1]

My Onan NHE 6500 just started with this problem. Starts fine and will run for 30 minutes with a/c on. Shuts off and will restart if I wait about 3 minutes and runs for another 30 or so minutes. If I try to start it before the 3 minutes, starter cranks but engine won't catch. Gas tank is over 3/4, oil is full, new air cleaner, so I'm at a loss.

[w4phj]

Possibly the oil is thinning out and reducing the oil pressure enough to trip off the generator engine. You may want to try 10W30.

[gbopp]

Oil level in the generator correct? When did you chamge the generator fuel filter?

Do the simple things first.