1998 Sportsman – Does the starter need to be grounded to the frame?

Hello, I’m working on my cheap (problematic) 1998 Sportsman that I picked up a few months ago. I pulled the starter out to rebuild it and it won’t spin unless it is grounded to the frame, even with the positive and negative leads hooked up. Is this normal or have I put something back together incorrectly?

Even with this weird grounding it was working for a while but now it seems to be seized, I pulled the recoil cover off and I can’t turn the shaft at all. Going to go pull it out again and see why its binding.

Also, these things are a pain to work on, you have to disassemble half the machine to get at anything. Are other brands the same or are they more service friendly?

Thanks