I definately sympathize with the OP feeling uncomfortable with sending the motor back to someone who displayed shoddy workmanship and created the problem in the first place. It's always much more respectable to do the right thing the first time, until having to when peer pressure forces your hand. Kinda like having a dentist appointment to get a tooth pulled that is bad and they pull the wrong one, novocaine wears off at home and you notice you still have the toothache...... You probably go to another dentist next time.
No worse than selling someone a car that is not 100% to their expectations. You offer for them to bring it back so you can determine what the issues are and they have already decided the trust is not there.
