Does it have an "on-off-auto" switch, or just "on-off"?. If the former, it needs to be in the "auto" position to shut off automatically. After that, what pressure did it shut off at before this problem? Once it reaches 65 psi, and is still running, can you feel air leaking any place? I think those have a plastic cover of sort over the controls, which you may need to remove to feel around the unloader, pressure switch, etc., but be very careful, as most of those components get very hot.