Paid boat repair shop to repair my boat. They have not given me my repaired boat motor. I get nothing but excuses for over a month.

These kinds of situations are extremely difficult. At this juncture, obviously the only party with whom you have dealt does not have control of the motor. Consider paying the machine shop yourself and then trying to collect the money from the repair shop. If need be, you can sue, but at least you'll have both your boat and the motor.