Jay, sounds like your Decompression release on your CV15 is shot! Do a compression test! When your pull that engine over is should only have about 75-90 psi. If your getting a reading of 120-150 psi then the decompression release mechanism on your Camshaft is shot or at least severly worn out. Pull the valve cover off the engine and make sure that both pushrods are still where they are supossed to be. It is very rare for a CV15 to shear a flywheel key, but you may want to check that as well.