@Ives1122 posted:something else to add that happened to me in the past….
I replaced the 6/32 screws that hold the motor in the body with slightly longer, new screws, and the right rear one was just long enough inside the motor block to interfere with the movement of the forward—reverse slide when the body was on. It made it just slightly harder to move when everything was tightened up, but you could manually force it if you pushed hard.
I think this was on the larger steamer, so it may not affect the smaller one, but something to check. Once i put the shorter, original screw back in, everything was fine.
Oh thanks goodness, I thought I was the only person who had this problem! 
But mine was on a piper that someone mistreated and put screws that were too long in the motor. Unfortunately they were long enough to bend the end of the slide enough that I couldn't get it working without taking it apart and bending it back
