It fires fine and idles fine. As soon as you put it into gear it moves just a short distance and then it sounds like someone threw a wrench in the gears and it sounds like it locked up but once you put it into neutral it fires back up.could be a lot of things
Might not be firing on all cylinders, for a bunch of reasons.
could be a short in the kill switch wiring if it is located in the shifter controls.
Start by checking compression and spark on all cylinders.
YesDoes the prop turn easy by hand when in neutral?