Sounds just like the one I just fixed for a guy. he said he put in a clutch and it will not release. He just got his blaster and just power shifted for a while. Brought the motor to me to fix. What I found was,,,first the cover had a crack and some bolts missing, took it off and he had 4 of the 5 screws holding the pressure plate. None of the screws were the right kind and wrong washers. The washer was too wide for the hole so it was clamping the clutch down. One of the inner basket bolt holes was broken off too. So I took all that off and then took the clutch basket off and found weird shims of plastic behind that. So I went to take the clutch rod out and because the clutch was clamped it mushroomed over the rod by the swivel arm side. Had to grind that down so the rod(which was also broken in pieces) would all slide out. I put my clutch from my motor with all my parts on like text book says. It adjusted great and works good,,,So what Im saying is,,make sure you have the right hardware,the basket lined up right, all the hardware tightened to spec,and test it before you put the cover on. you might have something like your kickstart spring fall into it and break stuff too..