All right, so the batteries sat for about 24 hours and they've all dropped down to 6.3-6.4 VDC...except one. That one is down to 4.3. I didn't check the voltage at the solenoid - I just shouted an obscenity and picked up my meter.
I guess something is going to ground? Think I'll load it up and drag it to the place I bought it this weekend. See if they can find a short or something.
Thank you all for the help. I'm more of an AC guy as opposed to DC (I don't know how something is going to ground sitting on four rubber insulators
) but by no means an electrician. However, I've learned more about carts in this past week than I knew before. I'll let you know what turns up.