The above suggestions probably will work, however if they do not, remove the glow plug and, after positioning the prop where you want it, fill the cylinder with fuel and re install the glow plug.

You now have a hydraulic lock with the load spread equally over the piston. Remove the nut and then drain the cylinder.

Don't use any more thread locking compound on your prop shaft. NEVER EVER use red Locktite unless your don't ever want to disassemble the parts again !!! That's a fact !