MGB: Dist vacuum advance

Can you guys think of any good reason to block the vacuum nipple at the carb (dgev), and not run a tube to the distributor (45de4)? Other than the diaphram possibly broken?

Thats what I discovered today on my recent purchase

Thanks for any clues

Sam

PO didn't know what to do with it?

Sam, there are a lot of guys who don't understand the benefits of vacuum advance and won't use it. I know I was one of those for years. So the PO might well have just thought he'd get better performance by blocking it off. About all you really acomplish is to reduce your mileage and perhaps cause the car to run a little warmer. The diaphragm is easy to check, if it's not bad then I'd reconnect the vacuum and time the car again.