I have a DG and an attitude indicator on the same venturi. It's the biggest Wag-Aero venturi that is supposed to run 3 instruments. In flight my vacuum gauge usually shows 2 1/2 to 4" of mercury. Sometimes, the attitude indicator will act strangely, rolling over or doing other odd things. The DG is always working fine. I'm trying to figure out what the problem might be.
My venturi is mounted on the pilot side, just aft of the engine cowling, on the part of the fuselage that is angled as it widens for the cockpit. So the venturi is parallel to the fuselage, but not pointing straight ahead. Could this be a problem? Where do most people mount a venturi on an Ercoupe? This set up has been on my plane since I got it, and I'm not sure that it ever worked 100% all the time. Before I send my attitude indicator in for a re-build, I'd like to figure out what the problem might be. If any one can help, I'd appreciate it. Randy Hougham Grandpa's Ercoupe NC87384
