I posted pictures at this link.

Here is a link that might be useful: flickr

Looks like the air vane is out of position. Did you install it 180 degrees out?

I agree that it's out of position. Funny thing is, I never took the air vane off. There must be a stop on the throttle disc, so I can't turn it 180 degrees. It seems that I need to take the air vane off now, but it's not clear to me how it comes off. Do I need to pull the throttle disc off first?

Facing the air cleaner , the air vane should be to the right side. If the vane has no spring tension, the collar beneath the vane needs to be turned counterclockwise to apply tension to the vane spring. final adjustment will have to be done after the carb is installed in the mower. Just move th wheel a couple of clicks at a time until the mower sounds like it running at full speed. A tach would be useful but not necessary.Regarding the air duct, I think it should go in first. Getting those gaskets to stay in place on the heat shield can be a pain. I used grease to kind of hold them in place.