5.5 LP Onan has started to backfire and quit

Fixed! It was definitely a propane supply problem. I got a new regulator and put a different tank with no oil in it and the generator started working much better. But when I put it under the big load of two ACs it would again starve for fuel. So we took everything out—big job!—changed plugs even though they looked okay and search out everything we could think of. We took apart the low pressure regulator that’s inside the generator and it looked good. But then because everything was out of the way we could finally see the breather tube or whatever you call it that allows the low pressure regulator’s diaphragm to move freely. At the end, hidden behind a wiring harness and the propane feed line, was a small screen that was totally clogged. We blew it out and everything is working great!! The clogged breather wouldn’t let the diaphragm open all the way and therefore wouldn’t let the full supply of propane to the mixer. I was impressed by how clean everything was as we tore into the generator. Propane really does burn clean. This generator has electronic ignition so it didn’t have much to tune up. We are all happy now. Thanks. And I’ve learned that the oil comes from over filling my tanks. My fault. I fill from my own big propane tank and apparently leave the fill on too long. I try to stop as soon as it spits liquid out the little hole that the bleed screw controls but sometimes have left it too long. Lessons learned.