I have a 15 kw Bryant stand by generator that runs on propane. The unit is actually made by Generac but has a Bryant/Carrier brand label. It keeps shutting down every few days because of low oil. The low oil indicator comes on and it shuts down to prevent damage. After I put a quart of 1.5 quarts of oil (synthetic 5w 30w) it runs fine. But shuts down again a few days later. I don't see any visible sings of oil leaking from the engine or filter, so I assume it is burning oil rather quickly. My neighbor has the same unit and his is doing the same thing. Has anyone experienced the same and know why and how to fix?