question about atwood motor
 

Does anyone know where you can purchase 25 degree pressure angle gears to mesh with the atwood motor output shaft? (other than the one we were supplied with)

That was why you were supplied with it:). Sorry, but it is not a common pressure angle. The other part of the cluster _is_ a common gear and you can interface with it.

This means that you will need access to machinery to mount the motor, the shaft for the gear cluster and at least one other cluster. You may have to to a machinist to have it done. Larry Barello posted a picture of a trial run he did, and some useful dimensions.

Good Luck