The VRO is a pretty simple & reliable device. However they do wear out over time. Mine has recently failed, and it's only due to cost that I'm not putting another one back in. My VRO lost the ability to keep fuel pressure up. I"ve been quoted $650 for a new VRO, or $116 for a standard fuel pump in it's place. I wont mind having to pre-mix my fuel as it never stays in the tank long enough to go stale.