Its a beautiful, warm, sunny day here in Moose Jaw for this November 18th, (shirt sleeve warm). WOW!
So I removed the motor pully from the naked Gem and learned a lot. Needless to say it was a tight fit on the motor shaft although the pully didn't have a key slot only the motor shaft. My 3 jaw pully puller did the job nicely I might add, slow and easy does it with aluminum.
Measurements: motor shaft diameter 7/8 ", length 2.25", set screw 5/16" x 18, motor shaft key slot is 0.027" wide just enough for the nose of the set screw to enter. Like I mentioned no key or sign of pully slippage. with only the one (1) set screw.