Without getting into the details too much.....
I replaced a blower motor assembly on my forced air furnace (motor/impeller...whole assembly... even though I only had a broken impeller blade)
now I am noticing moisture collecting in the furnace under the blower assemly..... not much to the replacement, but wonder if I am missing a gasket or something between the housing and the blower .... although none came in the kit.
What blower assy did you replace. If it was the inducer assy on a 90 plus you may need to use some silicone. But if it is the main blower assembly you have low air volume, probably due to some kind of restriction in air stream. You could also have a leaking condensate pan on your evaporator coil, or a plugged condensate drain. If you could let me know a little more I can pinpoint it for you.