Pull cord wonyu pull ôt retract

I habé a huasheng 49cc 4 stroke (engine model 142f) and im pretty sure the oil isi full, the pull cord wouldnt pull but 4 inches. I took the flywheel off and it functions fine, the flywheel rotor rotates about half a turn either way and locks up, after rtying to re-align the rotor and flywheel, also discovered it does not retract unless the disconnected. It sat 3 or 4 days in heavy rain. I needed to chamge a sparkplug, i overtighened the ol sparkplug and it fell apart, i got the last peice from behind the flywheel roter but had no effect. I already tried to turn it when the sparkplug was out to loose compression. Does has anyone had this probem that could help?