Fuel pressure gauge

[Iou]

My fuel pressure gauge has two lines one coming from the carburetor fuel line the second goes to the air intake for the carburetor. What is the purpose of this second line? Does the fuel pressure gauge vent gas through this second line?

 

[VA Maule]

I would suspect it’s a case vent/drain line should the Bourdon tube rupture and leek

 

[Cumulo]

reference port

I would suspect it’s a case vent/drain line should the Bourdon tube rupture and leek

That 2nd connection will also serve as a differential pressure ref if routed to the carb air box. That would normally be necessary for a boosted engine.

r