D/G
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
If you have a vacuum gauge, it should read 3.5 or greater if your venturi and speed is correct.
Another possible source of your problem might be a vacuum hose that has collapsed interior. Rare, but can happen. Also, a dirty/clogged filter can prevent the gyro from receiving sufficient air volume.
Lastly, you can remove the gyro and send it out for testing. (Most likely problem? Bad gyro if it's more than 3 years since last overhaul.)
Another possible source of your problem might be a vacuum hose that has collapsed interior. Rare, but can happen. Also, a dirty/clogged filter can prevent the gyro from receiving sufficient air volume.
Lastly, you can remove the gyro and send it out for testing. (Most likely problem? Bad gyro if it's more than 3 years since last overhaul.)
George is certainly right about the gyro. One thing you want to do is to disconnect and remove the regulator and clean it. It usually sits under the panel or on the firewall, sucking all the dust and particles into its filter which gets clogged and restricts proper flow. There was 2 on my plane when I bought it (also had 3 of 4" Venturis). With the help of a licensed avionics tech, we removed both regulators, cleaned and re-installed one; re-plumbed for 1 of 8" venturi and it works great. I did get all my air driven gizmos overhauled. JD