The primary metering block on my 4778-2 has a hose fitting and I was wondering what fore? I heard something about power valve control for blower applications but not sure or is it just a vacuum port? Any ideas never seen this before?

This thing is a factory new mystery carb????

Vaccum fitting on primary metering block is for ported vaccum. Some use it for ignition advance control.

Daaah is that all it is :rolleyes: This carb is kind of wierd so it threw me off....long story.

Thanks!