The last bota I had to help a buddy get started was a water bottle keeping the pto lever next to the seat from engaging all the way. Check all pto/nuetral/seat safety switches.
I have not heard any mention of a volt/ohm meter. You cannot troubleshoot an electrical/starting problem without one. How many volts is your battery putting out?
Problem solved and you were right--it was simple. Bad connection on the positive battery side. I missed it the first time around. I now have a volt/ohm meter to make life a little easier.