Question about the two petcock hoses

illuminance · Post by **illuminance** » Sun May 20, 2007 5:52 pm

I was wondering about the two petcock hoses running from the petcock to the carb. The larger diameter one is for fuel, and there is certainly fuel coming from it. But what is the lower one for? Is that a vacuum hose pulling air from the gas tank or something? There is no fuel that is supposed to be flowing from the lower hose, correct?

scooterpoot · Post by **scooterpoot** » Sun May 20, 2007 8:22 pm

The little canister thing they're connected to is essentially a vacuum switch. When vacuum from the engine is applied to the lower hose it allows fuel to flow through the upper hose.