I need to troubleshoot a 24 volt Duffy electric motor. I need wire diagrams, basic tests, and whatnot.?

This is an electric motor in a pontoon boat. The motor won't run. I've done a load test on the batteries and they seem fine. The manufacture, Duffy, won't help because my shop is not a dealer, and they only work with dealers. If anyone knows some basic electric motor troubleshooting tests I could run I'd like to hear some suggestions. This is my first electric motor and I'm kinda lost. I have no wire diagrams or anything else to guide me. I've done some simple internet searches and found nothing. My buddy keeps talking about Yahoo answers so I thought I'd try it with this problem.