Stating the obvious but is the muffler tight against the exhaust flange? If its loose and leaking it probably wont start at least not easily. Sounds like you had a loose screw or a lot of vibration, might want to just check and make sure everythings tight.

I would change glow plugs, check the needle valve setting, and check to see if the muffler coming off didnt somehow hit the throttle arm and move it out of alignment which will screw up your throttle settings. The little throttle arms on the .46 LAs are CHEAP and flimsy it may have bumped it and moved it. All you have to do is look into the throat with the radio gear on and make sure your throttle butterfly is still in the right position atn idle and full throttle.

Just some outside the box possibilities.