Changed blowe motor on by furnace today. After putting it back together the new is louder than the old. Never did it before. Does the squirrel cage need balancing, similar to a celing fan?

If it is a multi-speed motor make sure that you got your wires connected to the right terminals.

Is the blower wheel very dirty?

Squirrel cage was very dirty. Tried cleaning with a paint brush. Got a majority of it but not all.

I asked because a dirty wheel will cause it to be off balance, you may need detergent and water to clean the wheel, not the motor, I know I shouldn't have to say that but you just don't know :-)

Thanks, I'll try this weekend.