On Sunday, March 12, 2017 at 8:57:26 PM UTC-5, Danny D. wrote:
Pulled the Honda/Craftsman cord to start 'er up, and the cord has very
little tension on the return stroke.

http://i.cubeupload.com/q5oXeb.jpg

Pull stroke seems reasonably normal but the string won't rewind all the
way.

Leaves about a foot to a foot and a half loose.
What makes it go tight? Springs?

Pulled the cord, and the string doesn't go back.
I can coax it back most of the way, but then when I pull again, it doesn't
go back.

Any debugging hints?

Go to Harbor Freight and get a cheap tarp and cover the lawnmower with it. OR, a giant washtub upside down over the motor would help.