Sorry I forgot to update. But instead of the “penny” idea(because I couldn’t get it behind the piston) I grabbed two plastic spacers and put them on the piston and reinstalled. I can use the idle adjuster knob to adjust idle where I want the sled to sit and idle, then I removed the coolant lines from the thermowax and tied them together. I’ve got well over 1000kms on the sled and it takes a little longer to warm up but sled runs great otherwise.
All said and done, not a single problem since. It doesn’t move on it’s own now and she runs great!!