Bruce,

In that case, two other things to check are 1) that the incidence is identical for both wings and that any discrepancy is not being compensated for with aileron trim, and 2) that the wing tip wash-out is equal in both wings.

Something is making the left wing stall before the right, and it is likely one of those things. But again, check the elevator trim once more to see if the overall incidence is in the ballpark.