There was one square piece of sheet metal with a U-shaped cutout for the shaft that slides in the slots. You can see the no-paint silhouette. It was almost fully closed when I got the blower. There are also slots on the other side and it appears that they were tied together with a common adjusting mechanism at one time to regulate intake airflow. The other blowers of this type (Agri-Fab, Olathe, Toro) seem to have smaller intakes. We'll have to see.Looking good Bob.
Question: Do you think the intake openings are big enough to supply full flow through the output opening, or will you be restricting that down some to get higher velocity?